‘Did we just watch the greatest title fight of all time?’ Yan sees off Sandhagen in epic battle to claim a UFC belt again (VIDEO)

In his first fight since he contentiously lost his bantamweight title in March, Petr Yan survived a slugfest to see off American opponent Cory Sandhagen in a scrap hailed by some of their fellow fighters as an all-time classic.

Any designs Yan had on blasting Sandhagen out with his heavy-pressure style proved fruitless early on, the third-ranked fighter staying on his toes and out of distance while regularly landing in a tactically crafty performance.

After a tight first two rounds that set the tone for the contest, Yan floored Sandhagen with a spinning backfist in the third.

That would have been the beginning of the end for many competitors, yet Sandhagen, commendably, returned to his feet in what was becoming an increasingly compelling showdown.

Yan was the busier fighter in the fourth, sending in some shuddering body shots as his adversary retained his resolve and remained an evident threat.

The pair were competing for an interim belt in the continued absence from action of Aljamain Sterling, the man who won the title from Yan after he was adjudged to have been hit by an illegal knee during a fight the Russian was winning at UFC 259.

Sterling has been involved in numerous acrimonious exchanges with Yan since that controversy, and defeat for 'No Mercy' would have been a huge blow to his ambitions of winning the outright title.

As it was, Yan looked stronger in the fifth, although the bloodied Sandhagen showed his endurance by engaging in a toe-to-toe even after the closing bell had sounded.

The victor draped himself in his national flag as he learned of his unanimous points triumph.

"I knew he was going to move well but our gameplan was to pressure him a lot," said Yan, who was hit square to the head with a flying knee at the end of the first.

The 28-year-old then addressed Sterling. "Everyone knows I am the real champion," he claimed.

"I am here and I am ready to fight anyone, if it is [TJ] Dillashaw or the clown Sterling. I want to thank my team for coming here to bring so much support. Thank you, everyone."

Yan's nemesis, predictably, responded immediately on social media. "Brilliant fight, men," he said, giving a narrower win than Yan's official 49-46 decision on his scorecard.

"You earned this first ass whooping. Rest up and enjoy the work you did. I’ll see you soon."

Lightweight contender Michael Chandler was more generous in his appraisal. "Did we just watch the greatest fight of all time?" he asked ahead of his own encounter with Khabib Nurmagomedov victim Justin Gaethje on November 7.

Sandhagen held himself up against the cage as he tried to come to terms with his gruelling loss while Yan spoke.

"He's a hell of a fighter," conceded 'The Sandman', briefly taking Yan's hand and bowing to him.

"He was better tonight. I have nothing else to say. I want to fight the best in the world; I know that's what's going to make me the best martial artist I can be.

"I'm grateful I got to do it tonight and I'll take from it, I'll learn from it. Next time I face him, I'm going to win."