Petr Yan lost his UFC bantamweight title to Aljamain Sterling at UFC 259 after the Russian landed an illegal knee despite being notified by the referee about his opponent being grounded. For the first time in UFC history, we saw a new champion being crowned as the result of a disqualification.
Interestingly, the opening bout of the main card at UFC Vegas 21 saw a similar end as Eryk Anders landed an illegal knee on Darren Stewart in the very first round. However, instead of Eryk Anders being disqualified, the bout was ruled as a no contest. Petr Yan took to Twitter in the immediate aftermath of the fight to express his dismay at the results. Yan uploaded a tweet which he then deleted, accusing the Nevada State Athletic Commission of double standards.
Why Petr Yan was disqualified at UFC 259
Although both Petr Yan and Eryk Anders illegally kneed their opponents, there might be other factors determining the differing results to their bouts.
For starters, the illegal knee from Eryk Anders looked nowhere nearly as damaging as the one from Petr Yan which had left Sterling in massive discomfort. Referee Herb Dean also did not see the knee coming from Eryk Anders as intentional. On the other hand, the commentary booth was in chaos at UFC 259 as Khabib Nurmagomedov reportedly heard Petr Yan's corner directing him to knee a downed opponent.
Another major rule that comes into play is one adapted from boxing which requires a minumum of four rounds to transpire for a fight to be ruled anything other than a no contest. In MMA, that translates to at least 2 rounds being completed in a fight.
While Anders' knee came in the final seconds of the opening round, Petr Yan went to committ the error in the fourth round of the title bout. A huge exception to this rule however is the 1997 classic between Mike Tyson and Evander Holyfield where Tyson was infamously disqualified in the third round for repeatedly biting Holyfield's ear.