Unbeaten Naoya Inoue retained his undisputed super bantamweight world crown on Sunday, climbing off the canvas to stop American Ramon Cardenas in the eighth round in Las Vegas.

Inoue improved to 30-0 with his 27th victory inside the distance when referee Thomas Taylor halted the fight 45 seconds into the eighth round after a flurry of powerhouse punches by the champion, with Cardenas only able to cover up.

"Watching the fight, everybody is very much aware I like to brawl," Inoue said.