TRAINER John Costello admits Jamie Cox's second round defeat to John Ryder could prove to be a damaging one after he failed to beat the count at the O2 Arena.

A right- hook to the forehead from Ryder knocked the Swindon southpaw to the canvas, however, the 31-year-old was able to get back to his feet but it was deemed too late by referee Ian John Lewis.

The defeat is Cox's second as a professional after he was beaten by George Groves at Wembley Arena last October.

"What is hard is, when you have a kid as talented as Jamie, he has everything, because in the gym he beats anybody but it's about doing it under the lights," he said.

"He's like a son to me, I worship the ground he walks on but to see him throwing his talent down the drain, it's heart breaking.

"John Ryder is a good fighter, he has come into his own at super-middleweight."

Costello, who has been a member of Cox's team for several years, says Cox had all the attributes needed to claim a win in the capital.

"The whole lead up to the fight has been the best I've seen Jamie," he said.

"I was thinking if it was the George Groves fight coming around now, he would have been in a better place for that.

"Frustration set in early on for Jamie but I think he realised early on he was in a fight, knew that he could hurt Ryder and tried to force it.

"You've got to keep your head and execute your game plan when you've got a good fighter in front of you.

"The plan was to stick behind the jab, use his feet and keep some distance between him and John."