Jeremy Stravius produced a scintillating final leg as France stormed from behind to see off the United States, Russia and Australia and steal 4x100 relay gold at the world championships in Barcelona on Sunday.

Olympic champions in London last year, the French were fourth when Stravius dived into the water but he hauled in American James Feigen, Russia's Danila Izotov and James Roberts of Australia to touch in three minutes 11.18 seconds.

The United States matched their silver from London in a time of 3:11.42 and Russia pipped Australia to the bronze in 3:11.44.

Fabien Gilot's contribution on the third leg was also significant as he was the only man to go under 47 seconds, recording a split time of 46.9 compared to Stravius's 47.59.American swimming great Michael Phelps turned up to watch the world championships in Barcelona with his foot in a hefty support brace after injuring it on the golf course.

"It's just a fracture nothing bad, we're being very cautious right now," Phelps, who retired after last year's London Olympics, said in an interview posted on the website of swimming governing body FINA (www.fina.org) on Sunday.

"So I guess it is true you can get hurt on the golf course," added the 28-year-old Baltimore native, who won 18 Olympic golds and 26 world championship titles in his glittering career. He did not elaborate on how he sustained the fracture.

The swimming events started earlier on Sunday and Phelps said he was looking forward to being a spectator rather than a competitor for the first time.

"It's kind of weird being on this side of everything," he said.

"It is a little strange to be out and about in public and dressed up but I am excited to be able to watch some of the swimming this week and not be I guess as nervous.

"This is going to be my first meet seeing people swim since I retired so it's going to be very different and I'm not sure how I'm going to react but I'm looking forward to it."