Michael Phelps suffered his first defeat in International competition for four years when Paul Biedermann beat him in the 200metres freestyle.

The 14-time Olympic champion last failed to get gold when he was edged out by fellow American Ian Crocker in the 100m butterfly at the worlds in Montreal.

Phelps had not been beaten in the 200m free since the Athens Olympics in 2004 but Biedermann produced an astonishing swim to triumph by a body length and also set a new world record of one minute 42.00 seconds in the process.

The German has now claimed two gold medals and consigned two previously untouchable world records to history at the Foro Italico.

Biedermann has clearly benefited from donning the Arena X-Glide while Phelps has remained in his Speedo LZR, revolutionary last year but now overtaken by the all-polyurethane suits.

Phelps' coach, Bob Bowman, has recommended the swimmer does not swim internationally after this meet until the issue is fully resolved.

Phelps himself said: "I look forward to racing Biedermann next summer.

"It will be fun when swimming gets back to swimming."

Of his race, done in a time of 1:43.22, Phelps added: "Theoretically it was a pretty good swim for me.

"Three tenths off my best time after taking six months off.

"I'm not happy but I know I didn't train much this year."

Biedermann was understandably ecstatic, saying: "It's still hard for me to believe that I defeated a legend like Phelps.

"I won two gold medals and I still have to swim the relay.

"It is true that he has been training only for six months and he is not the same as at the Beijing Olympics.

"But the German team which I am part of is great."