Michael Rock struggled to acknowledge the role of the performance-enhancing suit he wore en-route to beating the greatest swimmer in history.

Rock had the Manchester crowd on their feet at the British Gas Duel in the Pool when he relegated Michael Phelps to second in the 200 metres butterfly in 51.46 seconds.

However, the Stockport swimmer was wearing a performance-enhancing suit, which will soon be outlawed, while the Olympic and world champion was clad in a Speedo 2010 textile-only outfit.

In no way was it a level playing field and in all probability Rock will not taste victory over the American again given the return to textile-only suits from January 1.

The 22-year-old insisted he was putting the victory into context as a mid-season swim during heavy training but did not want to accept his performance was aided by his Jaked suit.

When asked if he would tell his grandchildren he had beaten Phelps but in high-tech apparel, Rock said: "It's not every day you beat Michael Phelps. I just cling on to that. It's a great experience for me, a great achievement, and it will just all be different next year.

"We'll all be on a level playing field and I think that will be a great thing for the sport.

"It's just another step on my journey looking towards the future."

Reflecting on whether he had an advantage, Rock continued: "Possibly, if you look at it that way, but I just see it as a great training swim, a mid-season swim."

On whether he would beat Phelps in next year's kit, the law student added: "I can't speculate on the future."

Phelps, who was also beaten into third in the 200m freestyle, said: "What I'm looking forward to is being the best I can for 2012.

"I want to see who can keep themselves in shape and who can work the hardest.

"It will be more of a sport and not just putting on a suit."

The 24-year-old was gracious, adding: "I was beaten because he was more prepared than I was for this race.

"The race is over. He swam a better race than me, he was more prepared.

"I'd rather lose the races now than lose them when it really counts.

"These are all little baby steps to the big picture."

Rock's victory at the Manchester Aquatics Centre was the ninth for the E-Stars team, comprising swimmers from GB, Italy and Germany, as they went down to an emphatic 185-78 defeat by the USA.

Eight of those victories were by Britons, of which six came from the women's team, who maintained their excellent form.

Today, Fran Halsall won the 50m freestyle to claim her third victory of the meet, Lizzie Simmonds added the 100m backstroke to the 200m she won yesterday and Rebecca Adlington won the 800m freestyle.

As well as Rock, James Goddard won the 200m individual medley and Federico Colbertaldo was first in the 800m freestyle.

There were three more world records set by the USA today to add to their five yesterday, which takes the total set since the introduction of the Speedo LZR in February 2008 to more than 250.