Islam Makhachev defended his UFC lightweight world title on Sunday, wearing down Alexander "The Great" Volkanovski both on his feet and on the ground to secure a unanimous points decision in Perth.

Russia's Makhachev derailed the Australian's campaign to become just the fifth fighter to hold two world titles simultaneously in UFC history, despite a fiercely partisan crowd.

"So hard an opponent," a breathless Makhachev said after a thrilling top of the bill contest at UFC284. "I am the greatest fighter in the world right now."

The 31-year-old Makhachev stretched his unbeaten streak in the UFC to 12 fights and his overall record to 24-1 as he made good on his threats to overpower the smaller Australian, with the judges' cards reading 48-47, 48-47, 49-46.

The surprise from Makhachev was his striking, as he picked his shots with precision landing overhand lefts and probing rights.

The Russian also made four trademark takedowns to leave the energetic Volkanovski looking for answers.

A huge right from the Australian landed late in the fifth to raise local heartbeats but Makhachev held on.

Dagestan-born Makhachev has been schooled throughout his career by Khabib Nurmagomedov -– arguably the greatest fighter in UFC history -- and boasted 11 submissions on his record coming into Perth.

The expectation was that Makhachev would look to quickly take the fight to the floor but the Australian's fitness and ground defence managed to take it the distance.

It all came down to numbers with too many strikes landed by Makhachev and a greater number of takedowns executed.

The win moved Makhachev above Volkanovski in the UFC pound-for-pound rankings.

"I showed why I am number one," said Makhachev. "You guys have to improve more. I thought he was going to be easy on the ground but this guy, he proved me wrong."

Volkanovski had moved up from featherweight for the fight, looking to carve a place in history.

Only Conor McGregor (featherweight, lightweight), Daniel Cormier (light heavy, heavy), Amanda Nunes (bantam, feather) and Henry Cejudo (fly, bantam) had previously held two UFC belts simultaneously.

Instead it was Makhachev who was considering how he might secure his own place among the sport's all-time greats.

"I just need to fight some more tough guys," he said.

Volkanovski will likely defend his featherweight belt next against second-ranked Mexican Yair Rodriguez, who earlier won the interim belt with a second-round submission of American Josh Emmett to secure the promise of a title shot

"Just because I pulled up short tonight doesn't change a thing," said Volkanovski.

"I'll be back but now let me go and settle this featherweight division."

Australia's rising welterweight Jack Della Maddalena earlier lit up the arena when he knocked down veteran American Randy Brown and choked him out to make it four first-round finishes in his four UFC fights.