JAMIE Cox’s trainer John Costello claims that George Groves has made a huge error in judgement by picking the Swindon fighter for the opening round of the World Boxing Super Series later this year.

The unbeaten former Walcot amateur has been handed a dream opportunity in the eight-man knockout tournament when he faces the seeded Groves for his WBA Super world super-middleweight crown in the autumn.

Costello is in no doubt that 30-year-old Cox will become Swindon’s first world champion after being selected by Groves as his quarter-final opponent.

“When George said Jamie’s name he looked so confident,” Costello told the Advertiser.

“But when he saw Jamie’s reaction, you could see that confidence drain away in minutes.

“Jamie was as cool as a cucumber, George is a nervy character – you can see that by the way he fights, he is very jittery.

“George is the world champion, but if you ask James DeGale (IBF world champion and former Groves opponent) who wins, he’ll say Jamie Cox.

“People in boxing know what Jamie can do. Joe Gallagher (Callum Smith’s trainer) said before the draft it would be a mistake for George to pick Jamie.”

Costello was also quick to hit back at Groves for saying that Cox is too small for a super-middleweight and called the Londoner a ‘part-time professional’.

“Jamie is an athlete, he lives in the gym,” the Birmingham-based trainer said.

“George is younger than Jamie (by 19 months) but you wouldn’t know it to look at him.

“George abuses his body when he is not boxing, he struggles to make the weight – he is a part-time professional.

“What he said about the size is irrelevant and it won’t matter come fight night.”

Costello says that preparations for Cox’s world title shot have already begun and he is determined to help the WBA Continental belt holder, who is a 4/1 underdog against the odds-on favourite Groves, realise his dream.

“Jamie is made up to get this fight,” the trainer said. “He is very grounded, he knows this a chance to help change his family’s life.

“When people talk about his red mist, it is not because of his opponents, it is because he has been so frustrated with the situations that he has been in.

“Jamie is the happiest he has ever been and we are going to leave no stone unturned to make sure he becomes a world champion.

“I know all about George Groves, I used to take a lad down to sparring at the at Dale Youth gym, which was at the bottom of the Grenfell Tower.

“All the negativity that there is towards Jamie and this fight doesn’t bother us at all.”