Wrestling, BJJ, boxing, and kickboxing all have champions you can point to. Each gives a fighter ways to control an opponent, create openings, or finish a fight. Their strongest claims come from how those skills hold up against someone trying to impose a different game.
I'm using base to mean substantial formative training, which can include several disciplines. GSP started in karate and developed exceptional wrestling; Topuria's grappling foundation preceded the boxing he's known for. Crediting their success means keeping both parts of those histories in view.
Wrestling
Wrestling helps a fighter take an opponent down, defend a takedown, or get back up. A striker with dependable takedown defense can commit more freely to punches and kicks; a wrestler can force exchanges onto the ground.
Folkstyle emphasizes control and escapes, while freestyle gives more weight to exposure. Both prepare fighters to keep attacking through scrambles, when one takedown attempt can turn into several. Kamaru Usman was a 2010 NCAA Division II champion; Henry Cejudo won Olympic freestyle gold in 2008.
Daniel Cormier's career takedowns show how quickly a wrestler can put an opponent on their back. Getting someone to the ground and neutralizing their offense has become one of MMA's most successful gameplans. A dangerous striker can spend much of a round fighting to stand up, using energy on escapes while the wrestler lands punches or works toward a submission.
Regional grappling foundations
Dagestani grappling combines wrestling with judo and sambo. Khabib Nurmagomedov's wrist control and leg traps show why that approach became so effective in MMA. By tying up an arm and locking an opponent's legs together, he limits their ability to post a hand, turn their hips, or stand. They have to work to escape while he hits them, then risk being dragged down again when they reach their feet. That cycle made him relentless, exhausting to fight, and hard to escape from. Islam Makhachev won a combat-sambo world title in 2016, bringing another foundation for linking takedowns, control, and submissions.
Khamzat Chimaev's route ran from wrestling in Chechnya to further freestyle competition in Sweden. He keeps pursuing takedowns through changes of grip and position. Defending the first attack can leave an opponent exposed to the next, giving them little time to establish their own offense.
Georgia gives us different examples. Merab Dvalishvili trained judo and sambo for seven years before MMA. Ilia Topuria developed Greco-Roman wrestling and BJJ. Merab's repeated takedown attempts force opponents to spend rounds defending and recovering their stance. Topuria uses his grappling foundation to support an aggressive boxing game. Both can put opponents under pressure through very different attacks.
Brazilian Jiu-Jitsu
Royce Gracie won three of the first four UFC tournaments. Those events showed how submissions and positional knowledge could overcome size and striking power when opponents had little preparation for the ground.
BJJ teaches submissions, escapes, and how to recognize danger on the ground. A credible submission threat makes an opponent more cautious about takedowns, ground strikes, and scrambles: a careless movement can expose an arm or the neck. Reaching those positions and controlling them under punches still requires adaptation to MMA.
Charles Oliveira pairs his submission threats with pressure, striking, and clinch attacks. Opponents trying to disengage from his grappling can leave openings for knees and elbows. His BJJ shapes the choices they make even during a standing exchange. He won the lightweight title by stopping Michael Chandler with punches.
Muay Thai and Kickboxing
Years of striking competition teach distance, timing, combinations, and how to stay composed while someone is trying to hurt you.
Joanna Jędrzejczyk started in Muay Thai, bringing combinations, kicks, knees, and elbows into her MMA game. Defending takedowns and separating from clinches let her sustain striking pressure, making opponents deal with attacks at several distances.
Alex Pereira's GLORY championships at middleweight and light heavyweight preceded UFC titles in those same divisions. His compact punches and low kicks let him inflict damage with relatively small movements. Attacking the legs disrupts an opponent's stance and movement, making it harder to stay out of punching range.
Israel Adesanya's Muay Thai and professional kickboxing background produced a different approach: feints, stance changes, evasive movement, and counters. He draws opponents into attacks he can read and punish. Hesitation then gives him more room to control the pace and distance.
Boxing
Boxing develops punching accuracy, footwork, defensive reads, and the ability to punish an opening quickly. Conor McGregor's early training at Crumlin Boxing Club helped establish the hands and counter timing he later combined with kicks and a wider stance. A well-timed counter can make an opponent pay for closing distance, including when they're trying to reach a clinch or takedown.
Ilia Topuria is, to me, at the cutting edge of boxing training in MMA. His work with a pure-boxing competition team in Alicante included dedicated practice on mobility and timing. You can see it in his uppercut-to-body-hook combination against Damon Jackson and his defense and counters in the pocket against Josh Emmett. Changing targets between head and body makes an opponent adjust their guard; staying defensively sound at close range lets him answer back immediately.
His grappling also shapes the way he boxes. Topuria describes building his aggressive boxing around his jiu-jitsu. He can commit to exchanges knowing he has the skills to handle the clinch or ground positions that might follow.
Karate
Karate has a claim through distance management, sudden entries, and timing. A fighter who can strike from just outside an opponent's reach and exit quickly makes it difficult to trade punches or secure a grip. GSP began in Kyokushin, Lyoto Machida trained Shotokan from childhood, and Stephen Thompson started in his father's karate school at three before developing his kickboxing career.
Early McGregor also belongs in this discussion. His wide stance, movement, and ability to draw opponents onto counters often looked karate-like. Thompson has discussed that influence on McGregor's style.
Low kicks, takedowns, and pressure near the cage all demand adjustments to stance and timing. Being backed against the fence takes away room to retreat. GSP, Machida, and Thompson kept karate's distance skills as they learned to handle those threats.
Judo and Combat Sambo
Judo develops throws, balance, and transitions from a standing grip into ground attacks. Ronda Rousey followed Olympic bronze in 2008 with six UFC title defenses. She could throw an opponent from the clinch and move straight into an armbar, attacking before they had time to settle into a defensive position.
Combat sambo includes striking and submissions alongside takedowns. Fedor Emelianenko won four combat-sambo world titles and trained in judo and boxing. Linking throws to ground-and-pound and submissions forced opponents to defend through each transition, with little time to reset after hitting the mat.
MMA requires different grips from jacket wrestling and careful defense against strikes during those transitions.
How the bases compare
Wrestling helps decide where exchanges happen, BJJ makes ground exchanges dangerous, and striking disciplines give fighters ways to land damage and control distance. The strongest claim depends on the matchup and how well a fighter can impose those skills. Each base has produced champions who added the skills their opponents forced them to learn.
For individual careers, see my MMA GOAT ranking, or combine fighters' abilities in GOATMMAKER.