Rarely has a huge lead disappeared so quickly. Largely unheralded U.S. swimmer Klete Keller jumped in the pool for the final leg of the 4x200-meter freestyle relay a second-and-a-half ahead of Australian legend Ian Thorpe. In less than 30 seconds they were swimming shoulder to shoulder.

Thorpe closed the gap with the suddenness of a screaming squad car with flashing lights. Suddenly this was no longer an American rout. It was a race. And it looked as if Thorpe would bury Keller with his trademark power finish.

But Keller, making a point to take his breaths facing the side of the pool lined with cheering U.S. teammates rather than the closing Aussie, gave up plenty of ground, but not the lead. Thorpe swam a faster anchor leg than Keller, but it wasn't fast enough to prevent the U.S. upset Tuesday night.

"I was just trying to do my best for the guys and the country, trying to keep the lead," said Keller, 22, who finished fourth in Monday's high-profile 200 freestyle final. "It hurt like hell, but it paid off."

Hours after the U.S. team endured the embarrassment of a morning in which no American men advanced to the semifinals of the 100 freestyle -- which has never happened at a non-boycotted Olympics -- this quartet beat a heavily favored Australian team in one of its signature events.

"It's been a long time since we won this race," U.S. men's team coach Eddie Reese said. "To beat Australia, they have literally owned this race for the last four, five, maybe six years. We needed to do that."

Earlier, U.S. breaststroke specialist Amanda Beard won a medal in her third straight Olympics, this one a silver in the 200 individual medley. Beard nearly chased down Ukraine's Yana Klochkova with a furious breaststroke leg as she collected her fifth Olympic medal (one bronze, three silver, one relay gold).

"I'm very, very honored and excited and happy to have a silver medal, especially in an event like this, which is a difficult event for me," Beard said.

The U.S. relay team shared those feelings.

Given a huge lead by Michael Phelps (1 minute 46.49 seconds) at the start, Ryan Lochte (1:47.42) and Peter Vanderkaay (1:47.79) preserved it for Keller (1:45.53), who brought home the victory in 7:07.33. Thorpe (1:44.18) touched the wall .13 seconds later, leaving teammates Grant Hackett, Michael Klim and Nicholas Sprenger holding their heads. The Italian team finished third in 7:12.60.

"It was just a magic race, to be honest," Klim said. "We can't expect Ian to be winning relays for us all of the time. . . . We've been in the situation before where we've been on the other side and just touched-out the Americans. Unfortunately, that wasn't the case this time."

The victory provided Phelps with his third gold medal of the meet and second of the night. The first came in the 200 butterfly. And, perhaps most significantly, it restored what had been a rapidly crumbling respectability to a beleaguered U.S. men's freestyle squad.

Days after a crushing defeat in the 4x100 freestyle relay, the United States endured a disastrous morning of qualifying swims as Ian Crocker and Jason Lezak stunningly failed to advance to Tuesday night's semifinals, leaving the United States without a single swimmer in the men's 100 freestyle final.

The top 16 swimmers had moved on to the semis; Crocker finished 17th in 49.73 seconds and Lezak, 20th, in 49.87. Though Crocker might have been suffering from a sore throat, Lezak told his coaches he simply misjudged the race, underestimating the time he needed to advance.

Lezak, fourth in the 100 free at last year's world championships, was considered a medal hope here, and Crocker, a member of the last two U.S. world championship 4x100 teams, a favorite to advance to the final.

"It's not what they wanted," Reese said. "It's not what they expected. It's the worst of all scenarios."

Actually, things could have gotten worse Tuesday night, but Keller saw that they did not. Keller, who claimed a relay silver and 400 bronze at the 2000 Summer Games, has the misfortune of facing Thorpe and Hackett on a regular basis, meaning he owns a lot more silver and bronze than gold medals. But he said he isn't intimidated by either swimmer.

He said his biggest challenge was not swimming in Thorpe's shadow but trying to keep his mind blank.

"I just try to go out and not feel the pain," Keller said. "For the first three laps, I pretty much was numb. The last lap, it all set in: Your body starts burning and you go into oxygen debt. But that's what we train for, to deal with that."

The U.S. coaches provided a history lesson to the relay team members Tuesday afternoon, telling them about the 4x200 relay final at the 1984 Summer Games in Los Angeles, in which U.S. anchor Bruce Hayes barely held off Germany's Michael Gross as the United States won by four-hundredths of a second. The message: Pace yourself and finish strong.

In other words, do exactly what Thorpe did not do.

"Thorpe made a mistake," U.S. assistant coach Jon Urbanchek said. "Sometimes the adrenalin takes over and intelligence takes a backseat."

After the race, the Americans gathered in a circle and grabbed one another in a long group hug. The Aussies hung their heads and glumly shook hands, looking as if they had finished last.

"We are a little bit disappointed . . . because we have won this event so many times," Thorpe said.

The race provided another first for Keller.

"I haven't beaten him in an individual race," Keller said about Thorpe. "This is just as sweet, if not sweeter."