ROME (AFP) — Michael Phelps snagged his third gold medal of the swimming World Championships, crediting his 4x200m freestyle relay teammates with delivering the goods in a world record-setting victory.

Phelps, Ricky Berens, David Walters, and Ryan Lochte clocked 6 minutes and 58.55 seconds to shave one-hundredth of a second off the previous record of 6:58.56 set by a similar US lineup - lacking only Walters - in winning Olympic gold in Beijing last August.

Russia finished second in 6:59.15 and Australia took bronze in 7:01.65.

Phelps and Lochte each claimed his third gold medal of these championships.

They teamed on the victorious 4x100m freestyle relay squad, while Phelps won the 200m butterfly and Lochte the 200m individual medley earlier this week.

But Phelps thought he could have been better.

''I think I was kind of carried by my teammates tonight,'' Phelps said. ''I was a little slow in the first 100m, I split it well but I was a little slower than I wanted to be.

''I was probably half a second slower than I wanted but those guys were able to take control and Lochte swam well.''

Paul Biedermann, who broke Phelps's world record in besting the US star in the 200m freestyle, put Germany more than one and a half seconds up on the first leg.

But the Americans responded, with Lochte holding firm on the final leg against Russian Alexander Sukhorukov not long after taking bronze in the 200m backstroke.