Lightweight world champion Khabib Nurmagomedov defeated interim champion Dustin Poirier in their UFC 242 title unification bout in Abu Dhabi.
Nurmagomedov, 30, submitted America's Poirier in the third round on Saturday to make it 28 wins from 28 fights.
The Russian outwrestled Poirier over the first two rounds before securing a rear naked choke to cement his status as the UFC's number one 155lb fighter.
Numagomedov defeated Conor McGregor via submission at UFC 229 in 2018.
That contest in Las Vegas ended in a wild brawl between the two rival teams and left Nurmagomedov suspended.
After serving his ban, the Russian returned to face Poirier with the well-deserved reputation as one of the most dominant fighters in the world.
Poirier had captured the interim title with a thrilling win over current featherweight champion Max Holloway at UFC 236 in April.
It set the stage for a champion versus champion clash with the returning Nurmagomedov looking to re-establish his place at the top of the division.
And he did just that with a dominant display of wrestling and grappling that left Poirier with no answer as he relentlessly pursued a submission finish through three punishing rounds.
The finish eventually came after Poirier spied a potential submission of his own, as he timed a Nurmagomedov takedown attempt and locked up a tight guillotine choke.
But the Russian - a former two-time combat sambo world champion - remained calm and eventually managed to escape the predicament before transitioning to Poirier's back and locking up the fight-ending rear-naked choke that forced the tap at the 2:06 mark of the third round.
After the fight, Nurmagomedov donned one of Poirier's T-shirts and said he would auction it off to help raise money for the American's charity, The Good Fight Foundation.
But he would not be drawn on when he might return to the octagon for his next match-up, saying he needed to rest for a few days before addressing his next challenge.
Remarkably, Nurmagomedov's most likely next opponent, American former interim champion Tony Ferguson, has been booked to face the Russian star on four separate occasions earlier in their careers, with injury and illness forcing the cancellation of the match-up each time.
Now, with Nurmagomedov on top of the division and Ferguson the clear number-one contender, a matchup between the two may finally happen.
Felder edges Barboza
The night's co-main event produced another crowd-pleasing spectacle as American Paul "The Irish Dragon" Felder edged a split-decision against former foe Edson Barboza.
The matchup was a rematch from a bout between the pair back in 2015.
Barboza took the judges' decision on that occasion but, after a bloody, back-and-forth striking battle in Abu Dhabi, it was an emotional Felder's turn to have his arm raised in victory as he earned scores of 28-29, 29-28, 30-27 to pick up the biggest win of his UFC career.
And it was a good night for the two British fighters on the card, with Scotland's Joanne Calderwood picking up a hard-earned split-decision win over fellow women's flyweight contender Andrea Lee, while featherweight debutant Lerone Murphy produced a strong performance against the hotly-tipped Russian contender Zubaira Tukhugov.
Despite coming into the contest on three weeks' notice as a late replacement, Murphy got stronger as the fight progressed and eventually earned a split draw on the scorecards to keep his undefeated record intact.