PERTH: Islam Makhachev survived an exhausting five-round war of attrition to retain his UFC lightweight title on Sunday, scoring a unanimous decision victory over Alexander Volkanovski after a thrilling battle at a sold-out RAC Arena.

Stepping up a weight class in an effort to become champion in two divisions, featherweight champ Volkanovski put on a tremendous display at UFC 284, but came up just short.

The fight started with some cagey exchanges in the middle of the octagon, with both fighters landing some heavy strikes before Makhachev used his wrestling to take Volkanovski down, threatening with chokes from the back to end the round.

Having learned his lesson, the 34-year-old Volkanovski did a much better job of dealing with Makhachev's relentless wrestling in the next two rounds to keep the fight on the feet, but the left hand of the taller Russian was always a threat.

Makhachev reversed the tide early in the fourth, landing an early takedown in the centre of the cage and trapping Volkanovski in a punishing body triangle before dominating the rest of the frame with his grappling.

Volkanovski showed tremendous tenacity to counter yet another takedown attempt in the fifth round. He came blazing back, decking Makhachev with a big right hand and pounding his opponent as he sought a knockout finish, but to no avail.

"I showed why I am number one, they have to improve more," Makhachev said in a post-fight interview. "I am the best striker in the world right now."

All three judges gave the fight to the 31-year-old Russian to improve his record to 24-1, while Volkanovski registered the second loss of his professional career to drop to 25-2.

In the co-main event, Yair Rodriguez scored a second-round submission win via triangle choke to win the interim featherweight title, and he will likely meet Volkanovski to decided the undisputed champion.