The 20 Biggest Surprises in the UFC This Year

The unpredictable nature of MMA is one of the main things that draws so many fans to the sport.

Midway through 2011, the UFC has already given MMA fans plenty of surprises inside and outside of the Octagon.

As we prepare for the second half of the year, which will most certainly bring more shocking moments, let's take a look at the events that had our jaws on the floor in the first seven months of the year.

20. Lyoto Machida Sends Randy Couture into Retirement

We all knew it would happen eventually. But, at the same time, it seemed like the day would never come when the ageless Randy Couture would say goodbye to the sport for good.

Even when Couture announced that he would be making his final appearance prior to his UFC 129 fight with Lyoto Machida, some doubt still lingered in the back of our minds.

However, when Machida landed a leaping front kick that dropped the legend to the canvas, a sense of reality finally settled in to the minds of MMA fans. One of the great careers in the history of the sport had finally come to an end.

19. B.J. Penn Immediately Looks to Take Jon Fitch to the Ground

Heading into UFC 127, most expected Jon Fitch to immediately employ his usual game plan of taking his opponent down early and often.

While he does have an excellent ground game, few foresaw B.J. Penn trying to take Fitch to the ground. Rather, most anticipated Penn would try to use his outstanding takedown defense to pick Fitch apart with his boxing.

However, it was Penn who quickly looked to initiate a grappling match with Fitch. Initially, the strategy surprised Fitch, and Penn was able to take the first round on the scorecards.

Fitch fought back and earned a draw with Penn.

18. Danny Castillo Chases Joe Stevenson from the Lightweight Division

After suffering a decision loss to fast-rising George Sotiropoulos and getting hit with a hard punch from Mac Danzig, it appeared that the UFC was giving Joe Stevenson an extremely winnable fight against Danny Castillo.

However, Stevenson ended up suffering a third consecutive loss in a unanimous decision, which forced the former lightweight contender to make some changes to get his career back on track.

Stevenson made the move to featherweight, where he recently lost to Javier Vazquez. No official announcement has been made, but it would appear that this fourth straight loss could be the end of Stevenson's run with the UFC.

17. Jeremy Stephens Earns Come-from-Behind Knockout Against Marcus Davis

At UFC 125, Jeremy Stephens had fairly certainly lost the first two rounds of his fight against Marcus Davis. Knowing that he probably needed to finish Davis to win the fight, Stephens came out much more aggressive in the third round.

With less than three minutes remaining in the fight, Stephens knocked Davis out cold. The amazing come-from-behind victory for Stephens led to the release of Davis from the UFC.

Although still surprising, this performance probably would have found its way higher up on this list if Stephens hadn't already made a habit out of knocking opponents silly throughout his career.

16. Vladimir Matyushenko Makes Quick Work of Jason Brilz

After arguably beating Antonio Rogerio Nogueira in what ended up as a split decision loss, many began to label Jason Brilz as a dark horse in the light heavyweight division.

When Brilz returned for his next fight against Vladimir Matyushenko, most expected a very competitive fight. However, Matyushenko ended up plowing through Brilz in a 20-second knockout.

15. Dennis Siver Halts the Rise of George Sotiropoulos

After picking up his eighth consecutive win against Joe Lauzon, many believed it was only a matter of time until George Sotiropoulos received a shot at the lightweight belt.

With most of the top lightweights already penciled in for bouts, Sotiropoulos was given a fight with Dennis Siver at UFC 127. At the moment, Siver was perceived as a step backward for Sotiropoulos.

Siver shocked the masses, though, by completely negating Sotiropoulos' ground game with excellent takedown defense. After rocking Sotiropoulos multiple times, Siver took a unanimous decision victory.

14. Melvin Guillard Overwhelms Evan Dunham

Melvin Guillard has always had the athleticism to compete with the best in the lightweight division. However, few expected Guillard to be able to demolish Evan Dunham the way he did at UFC Fight for the Troops 2.

The win was Guillard's fourth straight win, suggesting that Guillard had finally put everything together to make a run at the lightweight title.

13. Diego Nunes Upsets Mike Brown

Prior to meeting Diego Nunes at UFC 125, Mike Brown had suffered two knockout losses in his last four fights.

However, those losses came against top featherweights in Jose Aldo and Manny Gamburyan, so many thought Brown still had something left in the tank.

In the first round, Brown looked solid, battering Nunes with knees to the thigh and landing a strike that caused the Brazilian's eye to swell shut.

However, Nunes mounted an outstanding comeback and took a split decision victory from the former WEC Featherweight Champion.

12. Rafael Dos Anjos Derails George Sotiropoulos

After having the best year of his career in 2010, this year has not been nearly as kind to George Sotiropoulos.

After an upset loss to Dennis Siver, Sotiropoulos took a fight with Rafael Dos Anjos. Dos Anjos was expected to be an opponent who would allow Sotiropoulos to get back on track.

However, Dos Anjos wasn't about to be a rebound opponent. He knocked Sotiropoulos out less than a minute into the fight and may have ultimately exposed the Australian as overrated.

11. Judges Award Nick Ring a Victory over Riki Fukuda

At UFC 127, Riki Fukuda appeared to have earned a fairly clear victory over Nick Ring in his UFC debut. However, the three individuals scoring the fight had a different opinion than most.

In a unanimous decision, all three judges scored the fight in Ring's favor. The decision was so controversial that UFC President Dana White decided to pay Fukuda his win bonus.

10. Frankie Edgar Forces Draw with Gray Maynard

After Gray Maynard put a beating on Frankie Edgar in the first round of their fight at UFC 125, it appeared that the UFC Lightweight Championship would be changing hands.

However, Edgar mounted one of the most incredible comebacks in UFC history, forcing a draw with Maynard to retain his belt.

The two will have a lot to live up to when they meet for a third time at UFC 136.

9. Darren Elkins Gifted a Win over Michihiro Omigawa

In one of the biggest robberies in UFC history, Darren Elkins was named the winner of a fight with Michihiro Omigawa at UFC 131.

In a bout that appeared to sway completely in Omigawa's favor, one judge inexplicably gave Elkins the advantage in all three rounds.

Omigawa was awarded his win bonus despite technically losing the fight.

8. Dustin Poirier Stuns Josh Grispi

Heading into his UFC debut against Dustin Poirier, Josh Grispi was considered one of the most talented featherweights in MMA. In fact, he had originally been scheduled to fight UFC Featherweight Champion Jose Aldo at that same event.

However, Grispi was completely overwhelmed by Poirier from the beginning of the fight. Poirier, who was making his featherweight debut in that fight, was not expected to put on nearly as strong of a performance as he did.

7. Brian Stann Becomes Middleweight Contender with Win over Chris Leben

After winning in his middleweight debut, Brian Stann was given a massive step up in competition against Chris Leben.

The prototypical gatekeeper, Leben was coming off three straight wins and was heavily favored against Stann.

However, Stann showed that he was going to be a force at middleweight by finishing Leben in the first round.

6. UFC Newcomer Brian Ebersole Upsets Veteran Chris Lytle

Originally expected to fight Carlos Condit at UFC 127, Chris Lytle was looking to make one last run at a welterweight title shot.

However, Condit was forced to withdraw from the bout due to injury and Brian Ebersole was named Lytle's new opponent.

A journeyman and UFC newcomer, Ebersole was a relative unknown who was expected to lose badly to Lytle. However, Ebersole's unorthodox attack threw Lytle off of his game and led to a unanimous decision win.

5. Last-Second Replacement Charlie Brenneman Shocks Rick Story

After Nate Marquardt was removed from his bout with Rick Story at the very last second before weigh-ins, Charlie Brenneman stepped in to compete in front of his family and friends in his home town.

Despite the support, Brenneman wasn't viewed as much of a threat to Story. Nonetheless, Brenneman used his wrestling to grind away a decision victory over the rising welterweight prospect.

4. Nate Marquardt Released from the UFC

Loved by the fans, Nate Marquardt seemed like one of those fighters who would always have a home with the UFC.

That was before Marquardt failed a medical exam moments before the UFC on Versus 4 weigh-ins.

The failed medical test resulted in Marquardt being pulled from his main event fight with Rick Story and released from the UFC.

3. Tito Ortiz Returns with Win over Ryan Bader

It was supposed to be his sixth straight fight without a win. It was supposed to be his last fight in the UFC.

Tito Ortiz wasn't given a chance in hell leading into his UFC 132 with Ryan Bader. However, that doubt fueled Ortiz to mount an amazing upset win with a first-round submission of Bader.

Not only did the win allow Ortiz to keep his spot in the UFC, it led to a fight with Rashad Evans, which could allow Ortiz to go from washed up legend to top light heavyweight contender in one month's time.

2. Cheick Kongo Knocks out Pat Barry While Practically Unconscious

In the main event of UFC on Versus 4, elite strikers Pat Barry and Cheick Kongo met in a fight that promised fireworks. Few expected what was about to take place, though.

After getting knocked silly multiple times by Barry, Kongo stood on wobbly legs and threw two haymakers at his opponent.

Barry fell to the canvas and Kongo raised a finger in the air in what was quite possibly the most amazing comeback MMA has ever seen.

1. Zuffa Purchases Strikeforce

Strikeforce appeared to be gaining a ton of momentum. The Strikeforce Heavyweight Grand Prix was becoming a massive success for the organization and champions such as Gilbert Melendez and Nick Diaz were becoming recognized as two of the best fighters in their respective divisions.

Then, out of thin air, Strikeforce was owned by Zuffa. Without warning, Dana White and his business partners, Frank and Lorenzo Fertitta decided to purchase the second most popular MMA organization in the world.

The purchase has allowed an endless number of possibilities for the UFC. Already, Jason Miller has been named a coach for the next season of The Ultimate Fighter and Diaz will fight for the UFC Welterweight Championship against Georges St-Pierre.

Sean Smith is a Featured Columnist for Bleacher Report MMA. For the latest insight and updates on everything MMA, you can follow Sean on Twitter here.