With his ninth race in eight days, double sprint champion Gay ran a devastating final curve on the U.S. 4x100 relay team to set up his triple. Only Carl Lewis and Maurice Greene have achieved such a feat before at a single world championship.

"The 4-by-1 put the icing on the cake," Gay said. "This was the 'funnest' medal I got."

Felix can join the select group of triple titlists if she can help the U.S. 4x400 relay team to victory on Sunday. The 200 winner got her second gold on successive days when the American women won their sprint relay late Saturday.

"It was my first relay tonight, it was a great feeling and I can't wait to do it again tomorrow," Felix said.

The women held back their celebrations until the men streaked across the line in first place soon after. Then, they set up the biggest group hug of the week.

After winning the 100 and 200, Gay showed no fatigue as he set up anchor runner Leroy Dixon for victory over the favored Jamaicans.

"I'm extremely tired, but my teammates told me to go and do it one more time and get it done," Gay said.

As he handed the red baton over to Dixon, Gay screamed "go" amid the din of the capacity 50,000 crowd of the Nagai Stadium.

And go he did, doing enough to hold off surging world record holder Asafa Powell, who ran a blistering anchor to earn Jamaica the silver.

Gay was already pumping the air before Dixon crossed in 37.78, .11 ahead of Jamaica. Britain was third.

The three golds set up Gay as the American star heading into next year's Beijing Olympics. Carl Lewis won three world golds in 1983 and 1987, combining the 100, 400 relays and long jump. Greene's three gold were in the 100, 200 and relay in '99. Lewis, of course, also won four gold at the Los Angeles Olympics in 1984.

"I didn't come into these championships thinking about three gold medals," Gay said, arguing the rivalry with Powell in the 100 had created enough pressure as it was. "I think that's why I got it accomplished."

To make the U.S. night even better, Brad Walker won the pole vault at 5.86 meters, edging France's Romain Mesnil on a countback. Germany's Danny Ecker took bronze at 5.81.

A night after winning the 200, Felix helped the 4x100 relay team build up a lead that even 100 world champion Campbell could not close on the anchor.

Torri Edwards threw her arms up in celebration as she held off Campbell by .03 seconds to win in 41.98 seconds.

Only Marita Koch of the former East Germany achieved triple golds among women at the worlds, at the inaugural meet in 1983.

Lauryn Williams left the blocks like a bullet, before handing over to Felix, who was already well into stride. With a good handover to Mikele Barber, the U.S. runners had built enough of a cushion for Edwards to thrive on.

Surprisingly, Belgium won bronze.

After the relays, the U.S. team easily led the medal table with 11 gold and 22 overall. Russia had 4 gold and 13 overall.

In two other events, the Olympic champion and world record holders added world titles to their collections.

With an unlikely comeback, Roman Sebrle collapsed with exhaustion after the concluding 1,500 meters to win the men's decathlon.

Meseret Defar equaled Sebrle's feat. She won the 5,000 with a cunning run that seemed as easy as Sebrle's feat was tough.

"I achieved the world record and I wanted the gold medal. Finally, I am the world champion," she said. The competition was poorer for the absence of Defar's Ethiopian teammate Tirunesh Dibaba.

A dual distance gold medalist at Helsinki, Dibaba skipped the 5,000 after experiencing stomach cramps in defending the 10,000 title.

In her absence, Defar ran a perfect tactical race to overtake Vivian Cheruiyot with two laps to go, kicking for home to finish in 14:57.91.

Kenyans Cheruiyot and Priscah Jepleting Cherono took silver and bronze.

Sebrle did not take the lead until the second-last of his 10 disciplines.

With 71.18 meters in the javelin, the 32-year-old Czech moved from third to first with only the 1,500 meters to go. He hung close enough to Maurice Smith in the last race to ensure a win, with 8,676 points.

Sebrle finished 32 points better than Smith. Dmitriy Karpov of Kazakhstan took bronze with 8,586.

"That was a crazy competition," said Sebrle. "Now I have a full collection of medals and titles, but my motivation still remains."

Sebrle had looked mostly sullen during Friday's opening when even the withdrawal of defending champion Bryan Clay could not get him close to the top of the standings.

But while Sebrle soared in the javelin, Jamaica's Smith struggled and recorded only 53.61 _ almost 10 meters off his best.

At home, Sebrle was considered a spent force. What made matters worse was a bizarre javelin accident, which left him competing with a reminder on his shoulder. Over the winter, he was hit by a javelin, which left a wound 12 centimeters deep.

Few would doubt him now.

In the only morning final, Australia's Nathan Deakes won the 50-kilometer walk in 3:43:53. Yohan Diniz of France was next in 3:44:22 and Alex Schwazer of Italy took bronze.

"I will remember for ever the feeling when I came into the stadium and it was clear I'm the champion," said Deakes, who was in tears as he approached the finish. "It was quite emotional."

On Sunday, the U.S. team will bid for a world record in the 4x400-meter relay after easily qualifying for the final.

After Jeremy Wariner led a sweep of medals in the 400 Friday, the nine-year-old relay world mark could tumble.