Stevie McKenna says he "laid into" Ryan Garcia in sparring sessions and believes the highly-rated American would suffer a crushing defeat against Luke Campbell.
The Irishman has been helping Campbell to prepare for an expected WBC 'interim' lightweight title fight against Garcia, with a date and venue yet to be confirmed as negotiations continue.
McKenna, an undefeated super-lightweight based in Los Angeles, has been brought in as a sparring partner for Campbell and revealed how he also traded punches with Garcia in the gym.
"It was a great spar, he's very fast," McKenna told Sky Sports.
"He's sharp, but I did four good rounds and I laid it into him. It was good work. It's a fight I would also like down the line.
"He didn't want any more, put it that way.
"He found it hard to handle my pressure. I'm a very come-forward, aggressive fighter and it was different for him."
Campbell is a former Olympic gold medallist who emerged with credit from a points defeat to Vasiliy Lomachenko and has relished a potential clash with Garcia.
"I'm well up for this fight," Campbell told Sky Sports.
"He is a big name, he draws a lot of attention. He looks like he carries power and he has speed.
"We'll soon find out, won't we?"
McKenna, who has won all four of his fights by stoppage, is confident Campbell would overpower Garcia, an opponent he would also like to face in the near future.
"Right now I would take it [Garcia fight], so I would," he said.
"Luke is looking really sharp. I think Luke would win by stoppage.
"He's [Garcia] at the stage in his career where he's 20-0, he has to take these fights, if he wants to make it to the top.
"It will be an interesting fight to say the least."
Watch Terri Harper against Natasha Jonas at Fight Camp this Friday from 7pm, live on Sky Sports.