Murata, the 2012 Olympic gold medallist, appeared to dominate the fight in Tokyo, flooring the interim champ in the fourth round and wobbling him on several more occasions.

N'Dam, who had survived relentless punishment throughout, sank to his knees as the scores were announced to audible gasps from the Japanese crowd.

Murata, who lost for the first time in 13 professional fights, began aggressively and a vicious right hook sent N'Dam crashing to the canvas near the end of the fourth.

The Japanese challenger went for the kill, unleashing a series of right-hand bombs that threatened to bring an early end to the fight.

N'Dam showed real grit to stay on his feet as his legs buckled twice more in the seventh round.

More often than not the former WBO champion's punches simply glanced off the gloves of Murata, who never looked to be in any serious trouble.