Callum Smith knocked out George Groves in the seventh round to become the WBA 'Super' super-middleweight world champion and win the World Boxing Super Series final.
The Liverpudlian landed a huge left hook halfway through the seventh round that sent Groves spinning back into a corner, and Smith followed it up with two body shots and an uppercut to send his opponent to his knees.
The tournament's No 1 seed was clearly struggling to recover and stayed down as referee Luis Pabon counted to 10, two minutes and four seconds into the round, at the King Abdullah Sports City Indoor Arena, in Jeddah, Saudi Arabia.
As well as becoming the WBA 'Super' champion, Smith retained his WBC Diamond belt and won the Ring Magazine title and the coveted Muhammad Ali Trophy.
It was 'Mundo's' first world-title fight but he leapt into the super-middleweight elite in style. Smith's accuracy and calmness shone through from the start and, although Groves came back into it midway through a crisp and close encounter, the challenger always looked in control.
The pair took a full 30 seconds to swap jabs and it was Smith's overhand right that was the first decent shot of the night which not only set the early pace, but was to be one of his biggest assets.
The 28-year-old slipped into gear and looked comfortable in the second and when Groves tried to make an impression he was caught with a couple of smart counter-shots.
Smith then had the No 1 seed in trouble midway through the third; Groves' low left landing but another accurate right shunted him back onto the ropes, where the Liverpudlian had him hanging on.
The 'Saint' clawed it back in the next two rounds with any concerns over his shoulder problem dismissed by razor-sharp and doubled-up jabs and several right hooks downstairs.
Groves found himself in trouble on the ropes again in the sixth, though, with the familiar and effective straight right from Smith jarring his head back. A left hook further underlined the challenger's array of shots.
Smith opened the seventh with a trademark overhand right that had Groves on the ropes again and, although he survived the first barrage, a brutal left to the body had the champion in all sorts of problems and he stayed down after a flurry of unanswered punches.
"I'm a big believer in my own ability and I believed I was good enough to become a world champion," Smith told ITV Box Office.
"I kept believing and tonight I reminded people of how good I am. It was a good fight, I felt I was beating him at his own game and winning.
"I got my big shots off first and he couldn't take it and I got the finish."
Groves admitted he was looking forward to catching up with his family after a long, arduous recovery to his shoulder, but insisted he will be back.
"We knew he could punch, he has height and reach as well so I didn't really want to trade with him," he said.
"I was landing myself, but so was he and he got the finish. The shoulder looked alright and it felt alright. I'm not here to make excuses, it worked. Callum was the better man on the night.
"I'm going to have a good rest, I'm not retiring, it's been a dogged year for me."