Boxing: David Price is left stunned by early clip around the ear

Count your stars: David Price staggers to his feet after being knocked down (PA)

David Price's world – and perhaps his world heavyweight title ambitions – came crashing down in the Liverpool Echo Arena last night when the previously undefeated British champion was sensationally beaten in two rounds by American veteran Tony Thompson.

Price, hailed as a potential contender for sport's biggest prize, now faces an uncertain future after being caught with a right-hand punch that stunned not only himself but the crowd in his home town.

He was upended after just two minutes 17 seconds of the second round by the 41-year old southpaw security guard from Washington DC, unfortunately answering the question we had all pondered: could he take it on the chin?

Well, it wasn't exactly his chin but the side of his head, almost behind his ear. The blow sent him reeling backwards and he almost turned a somersault on the floor. He managed to rise groggily but his senses were still scrambled and his legs made of rubber as referee Steve Gray wisely called a halt.

The last time the 29-year-old had been anywhere near such a parlous plight was in the semi-final of the Beijing Olympics when he was stopped, hurt and dazed, having to settle for a bronze medal against the Italian Roberto Cammarelle.Since then the 6ft 8in Scouser had won 15 pro bouts in succession, inflicting the same devastating endings on most of his opponents as he suffered himself last night.

The 18st 10lb Thompson, who was thought to have seen better days even though he is the top-ranked American heavyweight, was last seen six months ago losing to Wladimir Klitschko for the second time in a world title fight. He was supposedly a massive underdog against Price but the latter's tactics were unusually tentative.

"It's the punch you don't see that hurts you the most, and I didn't see it coming," said Price. "What can I say? He caught me on the back of the neck. I've ended plenty of fights like that myself, now it's happened to me. I got caught and that's it. That's heavyweight boxing. One loss like that is not going to make me walk away."

It is a major set-back to Price's world title aspirations. Thompson will be offered a return but he intimated he will now go after Price's rival, Tyson Fury. "I'll be back," said Price. "This is just a blip."

In an ironic twist Audley Harrison, 41 like Thompson and bombed out in 82 seconds by Price in his last bout, won the Prize Fighter series for a second time after stopping New Yorker Derric Rossy in the second round of the final. Harrison, looking more athletic than he has in years, also beat Dane Claus Bertino and Belfast's Martin Rogan. Doubtless he will want a rematch with Price.