Phelps, hoping to show he can make another run at Mark Spitz's Olympic record of seven gold medals, led off an American victory in the men's 400-meter freestyle relay today at Rod Laver Arena.

Jones was also part of the four-man team, becoming the first black swimmer in U.S. history to claim a world title.

While Phelps got off to a slow start, he rallied to put the Americans out front by the time Neil Walker jumped in the water. The Americans steadily pulled away, with Jones swimming the third leg and Jason Lezak bringing it home in a time of 3 minutes, 12.72 seconds.

It was the second-fastest time in history, eclipsed only by the world record of 3:12.46 turned in by the same foursome last August.

''That was a good swim for us,'' Phelps said. ''We wanted to get this event back on U.S. soil. We've swam the two fastest times the last two years. We're all excited about that.''

Phelps is hoping to swim eight events in Melbourne -- the same eight that produced six gold medals and two bronzes at the 2004 Athens Olympics. If his body holds up at these championships, he'll try again to take down Spitz's hallowed mark at Beijing next year.

Italy took the silver and France claimed bronze.

The Australians won the women's 400 free relay as Jodie Henry rallied to out-touch Kara Lynn Joyce of the United States.

The winning team also included Libby Lenton, Melanie Schlanger and Shayne Reese. They chased down the Americans, who led off with Natalie Coughlin and were out front after swims by Lacey Nymeyer and Amanda Weir.

But Joyce couldn't hold off Henry, who rallied to win in 3:35.48. The U.S. took the silver at 3:36.68, while the Netherlands finished third.

In other finals on the first night of swimming, Park Tae-hwan of South Korea pulled off an upset in the opening race, coming from behind to knock off Aussie favorite Grant Hackett in the 400 freestyle, while France world record holder Laure Manaudou cruised to an easy win in the women's 400 free.

Park made a furious sprint over the final 50 meters, passing three swimmers -- Hackett included -- before he touched the wall in 3:44.30 to become his country's first world champion. In fact, it was the first medal of any kind for the South Koreans in the history of the world aquatic championships.

There were no surprises on the women's side, though Manaudou seemed a bit disappointed not to break her own world record.

After taking down Janet Evans' 18-year-old record last May and going even lower three months later, Manaudou was nearly a half-second under record pace early in the race but faded at the end. She finished in 4:02.61.