Few pioneers of MMA could genuinely challenge the upper-echelon fighters that dominate the sport today.
Truth be told, most of MMA's early champs would need to majorly refine their games in order to flourish against modern top-tier fighters.
However, a specific fraternity of innovators, all of whom possessed avant-garde skill sets, could hack it against today's elite.
Here are 10 old-school fighters who could still reign supreme today.
Kazushi Sakuraba narrowly missed making the list, but only because the Japanese superstar never fully developed as a striker.
A catch wrestler, Sakuraba made due with a top-flight grappling arsenal that included one of the best single-leg takedowns in the business.
Any man who could trump four members of the famed Gracie clan (Royler, Renzo, Ryan and Royce) could certainly succeed in the sport today.
The UFC's original welterweight linchpin, Pat Miletich held the 170-pound strap for 931 days between October 1998 and May 2001.
Miletich did so by using a well-rounded skill set that was primarily predicated on his wrestling and submission chops.
The founder of the highly successful Miletich Fighting Systems, which produced multiple UFC champs, "The Croatian Sensation" piled up an 8-2 mark in the UFC, falling only to Carlos Newton and Matt Lindland.
Along with having an extremely balanced game, Miletich made the cut because of his intelligence and his grit.
There's a valid reason longtime UFC featherweight champ Jose Aldo loosely based his fighting style on fellow Brazilian Pedro Rizzo.
Aldo simply saw that Rizzo's modus operandi pleased both fans and promoters, an approach he wisely decided to mimic.
Rizzo mainly used his Brazilian jiu-jitsu black belt to ward off takedowns and keep his fights standing. "The Rock" inflicted most of his damage in the upright position, where he regularly brutalized opponents with devastating hand combinations and thunderous kicks.
Rizzo prevailed in six of his first seven fights in the UFC, including five by way of knockout. A weathered Rizzo last competed in May, where he lost a decision to Satoshi Ishii 23 days after his 39th birthday.
HBO ensured that fans would remember the dramatic demise of Mark Kerr by releasing the The Smashing Machine, a documentary that chronicled the struggles of the former NCAA Division I wrestling champ.
But before his personal issues derailed his career, Kerr represented arguably the sport's most promising heavyweight talent.
Kerr went unbeaten in his first 13 fights before breaking down mentally and falling into obscurity in the early 2000's.
Although he retired in 2009 following five consecutive losses, Kerr never lacked the talent or the tools to get back to the top of the heavyweight heap.
With better guidance and more self control, Kerr could have legitimately became a legend in the sport.
Despite sporting a pristine 11-0 MMA record, fans will truly never know how dominant Rickson Gracie could have become.
Recognized as the best grappler in the Gracie family, Rickson took his first pro fight in 1980 and his last in 2000. He won each of his 11 bouts by submission, 10 of which came in the first round. Only Yoshihisa Yamamoto managed to survive more than one round with Gracie.
Filmmaker Robert Goodman immortalized Gracie in the 1999 documentary Choke, which recounted the renowned grappler's experiences in Vale Tudo Japan 1995.
Had Gracie continued to test himself against the world's top middleweights, he could have easily found himself at the top of this countdown.
Although he just retired in 2013, Mark Coleman made his bones in the late 1990s and early 2000s in the UFC and Pride.
A former Olympic wrestler and NCAA Division I national champion, Coleman helped revolutionize the sport by perfecting the art of ground-and-pound.
Coleman used his barbaric style of flooring and mauling opponents to capture the first UFC heavyweight title at UFC 12. At the height of his career, he won the Pride FC Openweight Grand Prix in 2000.
Coleman deservedly gained entrance into MMA's most exclusive club when he got inducted into the UFC Hall of Fame in 2008.
Former UFC heavyweight champ Bas Rutten was just hitting his stride when a rash of injuries forced him to retire in 1999 at the age of 34.
The ever-improving Rutten learned from his early blunders and used those lessons to finish up on a 22-fight unbeaten streak. In that span, "El Guapo" won 11 fights via submission and seven by knockout. He also avenged two of his four career losses by besting Frank Shamrock (twice) and nemesis Masakatsu Funaki.
But Rutten didn't garner the No. 2 spot on this countdown solely on account of his impressive career-ending winning streak. Rutten landed at No. 2 primarily because of his aptitude to constantly evolve.
Rutten defined growth in MMA by balancing his strike-heavy attack with a rock-solid grappling repertoire. Like Shamrock, "El Guapo" prospered with unpredictability. Because his opponents didn't know how to prepare for him, they couldn't beat him.
Not to suggest that Rutten could get the best of UFC heavyweight champ Cain Velasquez, or even UFC light heavyweight champ Jon Jones. But having phenomenal athleticism and the propensity to adapt would definitely make Rutten a viable contender at either weight.
An underrated wrestler with a superb knack for scoring submissions and knockouts, Shamrock thrived on his ability to pull off the strange.
Shamrock captured the UFC middleweight title (later renamed the light heavyweight title) in 1997, when he armbarred former Olympic wrestler Kevin Jackson in just 16 seconds at UFC Japan.
In his next four scraps in the UFC, all of which were title defenses, "The Legend" finished with a slam knockout (Igor Zinoviev), a kneebar (Jeremy Horn), a submission from punches (John Lober) and a submission from elbows (Tito Ortiz).
Shamrock amassed 10 submissions and six knockouts in his storied 35-fight pro career, proving from 1994 to 2009 that he was born to fight.