Arguably the two best heavyweight submission specialists in the UFC will go head to head in Jacksonville on May 9 as Russia’s Alexey Oleynik takes on former UFC heavyweight champion Fabricio Werdum at UFC 249.

Oleynik has had an incredible 78 bouts in his mixed martial arts career, and faces arguably his biggest-name opponent this weekend in Jacksonville when he takes on former champ Werdum, who is making his UFC return after he was defeated by Russia’s Alexander Volkov in March 2018.

Following that fight, Werdum and Oleynik were expected to fight in September 2018, but when the Brazilian failed a USADA drug test after testing positive for trenbolone, Werdum was suspended for two years. However, his suspension was later reduced to 10 months, and now the former world champion is ready to return.

At his peak, Werdum was considered one of the greatest heavyweights of all time. He’s faced a who’s who of legendary heavyweights, and in 2014 he defeated fellow legend Mark Hunt to capture the interim UFC heavyweight title. The following year he upgraded his belt to the undisputed version when he dethroned Cain Velasquez in Mexico City and cemented his legacy as one of the best big men to ever step into the octagon.

Werdum lost his belt to Stipe Miocic in his first title defense and hasn’t really recovered since. He’s fought five times since then, with mixed results, as he picked up three wins and two losses along the way. Now, after a doping suspension, he hopes victory over Oleynik will propel him back toward the top of the division once more.

But in Oleynik, Werdum faces a tough, durable opponent with even more experience than his own. “The Boa Constrictor” has more submission finishes than Werdum has had fights, and his ability to finish fights with his Ezekiel Choke submission has led him to be respected as the world’s premier exponent of that particular technique.

Despite his 78-fight career, Oleynik has submitted just twice in that time, and will likely fancy his chances on the mat against Brazilian jiu-jitsu black belt Werdum, who will rate his own abilities in the grappling exchanges.

It could result in a fascinating grappling-based matchup between two of the most seasoned mat practitioners in the game, but who will get the nod?