Let's be honest here. Not every UFC main event is worth the $55 price tag associated with a pay per view. Thankfully, a solid co-main event can be enough to turn any borderline card into a must-see PPV.
Former champions trying to get back into title contention commonly find themselves in co-main event contests. Other times, a grudge match between two stars on the cusp of contention will take place in this spot. Depending on how stacked an event is, sometimes the co-main event is a title fight.
Taking a stroll through memory lane, here is a look at the 25 best co-main event fights in UFC history. Some of them are in this list because of their importance in the history of the sport. However, most fights earned their spot in this countdown due to their incredible excitement.
When the UFC made their inaugural trip to Abu Dhabi, they delivered not one, but two title bouts for fans. With Anderson Silva and Demian Maia doing battle in the evening's main event, a championship bout for the lightweight title was relegated to co-main event status.
B.J. Penn and Frankie Edgar did battle for five full rounds in a closely contested affair. To this day, some argue that Penn outworked Edgar, although it was the New Jersey underdog who had his arm raised.
Although neither man had broken through into the mainstream by the time UFC 94 rolled around, a light heavyweight affair between undefeated prospects Lyoto Machida and Thiago Silva captured the attention of the Las Vegas crowd.
With a combined record of 26-0 for the two fighters, this matchup was considered a possible title eliminator. With Lyoto Machida scoring an incredible knockout with only one second left in the opening round, he was able to leapfrog Rampage Jackson in the pecking order and fight for gold only four months later.
The Ultimate Fighter 2 Finale
After an incredible finale during the inaugural season, heavyweights Brad Imes and Rashad Evans had some big shoes to fill.
Thankfully for fans, they were up for the challenge. As the co-main event under Diego Sanchez vs. Nick Diaz, these tournament finalists gave every ounce of energy they had as they battled for 15 minutes.
Evans won a split decision and went on to win a UFC championship.
With stars like Dan Henderson, Shogun Rua, Wanderlei Silva and Urijah Faber on the card, fans certainly were not complaining about the lack of a title fight at UFC 139.
In the evening's co-main event, Silva took on former Strikeforce champion Cung Le in a thrilling battle between old-school knockout artists who hunt for a spectacular finish at all costs.
Le nearly finished off "The Axe Murderer." However, the former PRIDE champion was able to rally through and score a TKO victory late in the second round.
After coming up short in his UFC debut, Brock Lesnar knew that his career was on the line in a matchup against Heath Herring.
From the opening bell, this matchup was all Lesnar. As soon as the fight began, the WWE superstar leveled Herring with an enormous overhand right that sent "The Texas Crazy Horse" flipping backwards like a drunken gymnast.
This fight showed how dominant Brock could be when facing a respected veteran of the sport and earned him an immediate title shot against Randy Couture.
For years, fans of boxing tried to make the claim that their sport was better and that anyone who fought in their ring would decimate an MMA fighter with ease. At UFC 118, heavyweight champion James Toney decided to test that theory when he took on UFC Hall of Famer Randy Couture.
In a result that surprised exactly zero MMA fans, Randy Couture immediately took James Toney down, where he gave the boxer a quick taste of ground-and-pound before latching onto an arm-triangle choke for the victory.
This bout served as the co-main event under a rematch between Frankie Edgar and B.J. Penn.
Funny how you don't hear of any boxing champions trying to compete in MMA anymore.
It's not often that you get to see an alien life form putting a beatdown on one of the greatest pound-for-pound fighters in the world.
OK, maybe that's not an alien. Maybe it's featherweight contender Mark Hominick with one of the nastiest hematomas ever seen in the history of combat sports.
Aldo dominated the early goings of this matchup, which made Hominick's comeback all the more impressive. However, it was too little, too late for the Canadian, as Aldo won too many rounds to possibly lose a decision.
At UFC 129, Zuffa gave fans a pair of title fights as they went to the Rogers Center in Toronto. With Georges St-Pierre taking on Jake Shields in the main event, this scrap for the 145-pound championship took the co-main event slot.
As the first coaches fight in The Ultimate Fighter history to be postponed, there was great anticipation for the grudge match between former welterweight champions Matt Hughes and Matt Serra.
Serving under a title bout between Rashad Evans and Lyoto Machida, this scrap was a back-and-forth affair that saw Serra nearly earn a knockout in the first round, get controlled by Hughes in the second and have an insanely close third round.
As the scorecards were being prepared, it was anyone's guess who would emerge with their arm raised. In the end, Hughes was given the nod by all three judges.
As 2011 came to a close, there were a lot of big fights on the docket. Jon Jones was defending his title against Lyoto Machida, and just around the corner was the UFC debut of Alistair Overeem.
Because of those bouts, it may have been easy to overlook a rematch between submission specialists Frank Mir and Antonio "Minotauro" Nogueira. After all, both fighters were approaching the end of their primes, so this bout didn't have any perceived title implications.
However, in an incredible encounter, Nogueira hurt Mir badly during the stand-up exchanges, and when he looked to finish the fight on the ground, Mir slickly maneuvered himself into position and snatched up a kimura.
Because of Nogueira's incredible jiu-jitsu wizardry, he refused to tap out from the hold. After nearly rolling to safety, it briefly looked like he would escape. However, Mir continued to crank on the arm until it eventually snapped.
With Anderson Silva in your main event, you don't exactly need to put much talent in the co-main event in order to sell. However, the UFC prefers to create enormous cards whenever they can. For that reason, fans at UFC 97 were treated to a battle between Chuck "The Iceman" Liddell and Mauricio "Shogun" Rua.
As two of the biggest stars in the history of the light heavyweight division, this matchup was a dream fight for many fans who recognized each fighter as one of the best in the world.
Shogun knocked out Liddell with authority late in the first round and used the momentum of this victory to earn a title fight against Lyoto Machida.
When Johny Hendricks and Carlos Condit met at UFC 158, the fight was unofficially a title eliminator in the welterweight division. As the No. 1 and No. 3 ranked contenders to GSP's championship, whoever emerged victorious from this scrap would be next in line to fight for gold.
Both fighters had their skills on full display. Hendricks used his incredible wrestling to score takedowns at will, while the bottom game on Condit allowed him to threaten with submissions, strike from his guard and quickly return to his feet without absorbing damage.
However, this fight was far from a grappling contest. Each fighter landed power strikes on a regular basis during stand-up exchanges, yet both had a strong enough chin to remain upright.
Hendricks won the decision in this Fight of the Night. We will soon find out what he does with this momentum, as "Big Rig" is scheduled to face GSP later this year.
Heading into UFC 111, Frank Mir and Shane Carwin were top contenders. However, with the champion sidelined by a bout with diverticulitis, the UFC brass elected to let the contenders wage war for an interim belt.
It was a win/win situation for fans, as Carwin was an undefeated knockout artist, and Frank Mir was the only man to ever defeat the reigning champion, so a rubber match would be a box-office smash.
Carwin had his power striking on full display in this matchup, as he repeatedly hurt Mir with uppercuts before finishing him off with punches from back mount.
This bout served as the co-main event under a title match between Georges St-Pierre and Dan Hardy.
Heading into a title fight against Carlos Newton, Matt Hughes wasn't yet the dominant force that we saw him become. In fact, in his most recent UFC appearance, Hughes was submitted in only 20 seconds by Dennis Hallman.
This fight is historic for its finish. With Newton locking in a triangle choke on Hughes, it appeared that we were only moments away from seeing a successful title defense. However, Hughes refused to accept defeat, lifted Newton into the air and powerbombed him a la Scott Norton.
The knockout scored Hughes his first world title and began his journey towards the UFC Hall of Fame.
After a lackluster performance from Anderson Silva at UFC 97, Dana White decided that he needed to put "The Spider" in a position where excitement wasn't an option. That's why he booked Silva in a light heavyweight matchup against the always-thrilling Forrest Griffin at UFC 101.
Serving as the co-main event under B.J. Penn vs. Kenny Florian, this matchup put Silva's striking dominance on full display.
Every shot Griffin tried to throw, Silva easily avoided. The middleweight champion peppered his opponent with shots in a seemingly effortless way before scoring a knockout in the first round.
When the UFC made its Australian debut, it looked to book stars who were already popular in the Far East against some of the hottest rising talent from the West. The main event had former PRIDE champion Antonio Nogueira versus prospect Cain Velasquez, and a similar matchup was booked with second billing.
Longtime PRIDE champion Wanderlei Silva met Michael Bisping in a matchup between an old-school brawler and a tactical striker. The affair was thrilling from top to bottom and one of the closest bouts to ever reach the scorecards.
Ultimately, Silva scored a unanimous decision victory in what was his middleweight debut. In an absolute robbery, this matchup somehow did not win Fight of the Night honors.
When the UFC closed their lightweight division, few expected B.J. Penn to be able to jump to welterweight and dethrone dominant champion Matt Hughes. However, that is exactly how it went down.
Penn used superior technique to take the back of Hughes and lock in a nasty rear-naked choke that would earn him his first world title.
Bonus Fight: The rubber match between these two men occurred as the co-main event of UFC 123.
Although that fight didn't have the action of their first matchup, there was tremendous hype and a killer finish. Penn won that bout via knockout only 21 seconds into the first round.
As we all know, former WWE champion Brock Lesnar became the most successful professional wrestler to cross over into MMA when he won the UFC heavyweight championship from Randy Couture. However, we all have to start somewhere. Lesnar made his promotional debut at UFC 81 in a matchup with former champion Frank Mir.
Lesnar dominated the opening moments of the bout. However, a convenient stand-up from referee Steve Mazzagatti allowed Mir the opportunity to get out of a bad situation.
Unless you've been living under a rock or watching MMA with your eyes closed, Mir is one of the greatest submission fighters to ever step into the cage. He is amazing at taking the smallest of openings and finding victory.
Upon scoring his second takedown, Lesnar made a rookie mistake and Mir took full advantage by latching onto a kneebar and scoring the tapout only 90 seconds into the opening round.
When Mauricio "Shogun" Rua made his long-awaited debut in the UFC, few expected Ultimate Fighter winner Forrest Griffin to be more than a sacrificial lamb to the PRIDE standout.
Griffin shocked the world by staying competitive with Rua and spoiling his debut with a rear-naked choke with only 15 seconds left in the final round.
This matchup served as the co-main event under a matchup between Chuck Liddell and Keith Jardine.
After three wins inside the Octagon, the UFC brass decided that Ultimate Fighter winner Forrest Griffin was ready for a major step up in competition. The man elected to give him this opportunity was none other than longtime light heavyweight champion Tito Ortiz.
Ortiz and Griffin engaged in an absolute war that earned them 2006 Fight of the Year honors. Many felt that Griffin did enough in the last half of the fight to steal a decision, but two of the judges disagreed.
Ortiz won a split decision in a fight that served as the co-main event under Tim Sylvia vs. Andrei Arlovski II.
UFC on FOX 1
I'm not positive that this fight counts as a co-main event. Technically, it took place right before the main event of UFC on FOX 1. But this fight was not aired on the main card, due to the one-fight nature of that broadcast.
In a lightweight title eliminator, former WEC champion Benson Henderson met longtime UFC veteran Clay Guida in a thrilling affair that saw the long-haired warriors battle from pillar to post in hopes of a finish.
Unfortunately, a finish never came and it went to the judges' scorecards. Henderson had his arm raised after a fight that was a candidate for 2011 Fight of the Year.
There was a lot of pre-fight excitement leading up to this battle. Originally scheduled to be Akiyama vs Wanderlei Silva, the fight was changed with less than two weeks left after Wandy pulled out due to an injury.
When Chris Leben agreed to take the fight on less than a fortnight, he was viewed as a courageous fighter who was trying to be a team player. So when Akiyama hinted that he planned to drop out of the fight due to Leben being an unworthy opponent, fans were instantly up in arms.
In the end, we saw Leben and Akiyama throw bombs at one another, with the Japanese fighter getting the best of the exchanges and likely heading towards a decision win. With both men clearly exhausted and Leben stuck on his back, The Crippler summoned the strength to throw a Hail Mary and lock in a triangle choke.
The battle won Fight of the Night on an incredibly stacked UFC 116 card.
In a night of championship rematches, Matt Hughes and Frank Trigg served as the co-main event under Liddell/Couture II.
Although their first fight was a thrilling battle, the second encounter surpassed the first by a long shot.
After Trigg dropped Hughes with a low blow (that went unnoticed by the referee), Twinkletoes locked in a rear-naked choke that was only moments away from ending the fight.
However, as if trying to film the closing scene to a fight movie, Hughes summoned inhuman strength, lifted Trigg into the air and charged across the cage before slamming him to the mat.
Just for good measure, Hughes locked up a rear-naked choke of his own to earn the stoppage in the first round.
As 2012 came to a close, nearly every MMA publication had already released their winner for Fight of the Year.
Apparently, that lit a fire under lightweights Joe Lauzon and Jim Miller, who were scheduled to compete on the December 29 card.
Serving as the co-main event under Junior dos Santos vs. Cain Velasquez II, these fighters engaged in one of the bloodiest battles of all time after the relentless Miller opened up a tremendous gash on Lauzon's face.
Lauzon refused to quit, and these men gave every ounce of energy that they possessed while hunting for a finish. One of the most dramatic moments of the fight came in the final 30 seconds when J-Lau dove in for a flying heel hook.
Miller had his arm raised in the end, but there were absolutely no losers in this fight.
What once could have been the battle between reigning champions became a fight between two former champions who were both coming off of back-to-back losses. Although the glitz and glamour behind this match was lost, there was a lot of pride on the line.
Power punches were thrown around like mad, and neither man was willing to back down. The Ice Man scored big in the second round by opening up a cut on Silva, but the PRIDE star would win the round.
Liddell pulled out a decision against The Axe Murderer in 2007's Fight of the Year.
The Ultimate Fighter Finale
Anyone who realized that Griffin vs. Bonnar was the co-main event of the inaugural Ultimate Fighter Finale would have to know that this fight was taking top honors in our countdown.
UFC president Dana White called this contest the "most important fight in UFC history," and he was right. As fans tuned in to the card, they saw two reckless fighters going toe-to-toe and refusing to take a step backwards for 15 minutes.
Fans have voted this the greatest fight of all time and for great reason. I've included it for you here, in its entirety.
Andrew Saunders is a featured columnist with Bleacher Report MMA. Following him on Twitter makes you more attractive to the sexual partner of your choice. Do it now.