The United States’ Michael Phelps laughs as he listens to the national anthem after winning the gold in the men’s 400-meter individual medley at the Beijing 2008 Olympics today.

BEIJING — With every race Michael Phelps swims, his celebrity grows. Cheering him this morning at the National Aquatics Center in his first final of the Beijing Games was President Bush, who arrived minutes before the start of the 400-meter individual medley with, his wife, Laura, and his daughter Barbara, and his father, the former President Bush, in tow.

If it is possible to upstage a sitting president, Phelps did it. Ahead of his world-record pace from the first 50, Phelps pulled away from his American rival, Ryan Lochte, on the breaststroke — his weakest leg — to win going away in 4 minutes 3.84 seconds.

Lochte, who led at 150 meters, faded to third, behind Hungary’s Laszlo Cseh, who was timed in 4:06.18.

Phelps swam 1.41 seconds faster than his world-record time at the U.S. Olympic trials in July. His face widened in surprise when he saw his time on the large videoboard. He glanced at the stands, where Bush was vigorously waving an American flag, and gave him a nod.

“That’s a pretty special feeling,” Phelps said.

The breadth of Phelps’ burgeoning popularity was evident in the mixed zone afterward. It was like a U.N. assembly, with journalists from around the world pressing against the barricade, straining to make a connection. When Phelps stopped to answer questions, the surge was so great he stepped slightly back and said: “Whoa. Don’t push.”

Phelps acknowledged that Lochte and Cseh pushed him in the first half of the race. “I wasn’t comfortable after the 200,” he said, laughing. The back half of the race used to be where Phelps struggled, but no more.

Since 2004, Phelps has shaved almost five seconds off his world record in the 400 IM, with all of his improvement coming in the back half, especially on the breaststroke leg.

His performance on the walls has been crucial to his improvement. Today, he went into the final turn with a half-body length lead over Lochte and Cseh and emerged with a body-and-a-half-length advantage. Among those who looked on in awe was Eric Shanteau, who finished third in the 400 IM at the 2004 trials. Shanteau, who qualified for the 2008 Olympic team in the 200 breaststroke, recently described Phelps’ final burst — which propelled him to victory at the trials — as “incredibly, ridiculously hard to do.”

He added: “The event starts to hurt halfway through it. So for him to do what he does after that last turn and go that fast, it’s pretty much inhuman.”

The 400 IM is one of three events, along with the 200 butterfly and 200 IM, that Phelps has ruled with a pumped fist. The world record in the event has been his since August 2002, and he has lowered it eight times in that span. The gold was his ninth Olympic medal, leaving him two shy of the all-time leader, Mark Spitz, who collected his haul in 1968 and 1972.

This was the first time in three Olympics that Phelps had swum a final before lunch. Morning final, evening final, it makes no difference. Phelps’ body clock, it seems, is hydropowered. The water has always been a welcoming place for him. As a child, it was a sanctuary, a place where he could escape the mean kids who teased him about his big ears. Now it is the one place where he can go to get away from the trappings of fame — the autograph seekers and the star-struck.

Long before he had the likes of Lochte and Cseh to inspire him, Phelps was motivated by his tormenters. His mother, Debbie, remembered an 11-year-old Phelps emerging in tears from the locker room at Towson University, not far from his Baltimore home, during a swim meet because two boys from another team were making merciless fun of him.

Four years later, in 2000, after Phelps qualified for the U.S. Olympic team in the 200 butterfly, one of those boys came up to him in the stands at the Indiana University-Purdue University natatorium to congratulate him. As Debbie Phelps remembered recently, the kid said to Phelps, “Remember me? I swim with …”

Phelps looked him in the eyes and said, “I don’t seem to recall who you are.” After the boy left, Debbie Phelps said she turned to her son and said, incredulous, “Michael, you really didn’t remember him?” He told her: “Yes I did. But I was not going to give him that sense of satisfaction.”

Bob Bowman, who has coached Phelps for the last 12 years, said: “I think it pretty much goes in line with Michael’s way of operating. Whatever comes up he can turn into motivation.”

It is a thin line between vindication and vindictiveness, but somehow Phelps manages to stay on the positive side of it. “Most people can get sidetracked by things like that,” Bowman said. “Instead of using it to improve what they’re doing, it takes away from what they’re doing.”

Looking back on his childhood, when being singled out was a bad thing, Phelps said, “It bothered me at the time, but it definitely made me a stronger person.”

As Phelps’ legend grows, so does his popularity. The last time he checked his Facebook page, he had more than 4,300 friends. And then there is President Bush.

All of which does not impress Phelps much. All the hotheads and cold shoulders he endured as a child have inured him to celebrity’s charms.

“It’s funny,” Phelps said. “Every now and then you get on Facebook and you have people you see and you’re like, ‘Wow, I went to school with them, and they never said a single word to me, and now they’re trying to be my friend.’ I think it’s funny.”

Phelps is getting the last laugh, and gold medals aside, it is hard to place a value on that.

Phelps wasn’t the only swimmer to dazzle on what figures to be another assault on the record book over the nine-day meet.

Stephanie Rice of Australia went out extremely fast and held on at the end to win the women’s 400 IM in 4:29.45 — nearly 2 seconds faster than the world record of 4:31.12 set by Katie Hoff at the U.S. Olympic trials.

“I sort of turned around and thought I saw 4:31 and I was thinking, ‘That hurt a lot for a 4:31,’ ” Rice said. “But when I walked over and saw the 4:29, I thought, ‘That’s amazing.’ ”

Kirsty Coventry of Zimbabwe also went under the old mark, but only got the silver for the second-fastest swim in history, 4:29.89. Hoff couldn’t match her performance at the trials, settling for bronze in 4:31.71.

“It was a tough race, but I can’t really be mad,” Hoff said. “I was only like a half-second off my best time, so I’m happy to get my first medal of the Olympics.”

She was a frightened 15-year-old when she competed at her first Olympics in Athens, actually throwing up after her first event. She failed to win a medal in either of her two races.

This time, nerves weren’t a problem. She simply couldn’t keep up with Rice.

“I was trying,” Hoff said. “I didn’t have it at the end.”

The team from Down Under didn’t fare as well in the men’s 400 freestyle. Park Tae-hwan of South Korea won the gold medal, snapping Australia’s dominance of the event at the Olympics.

Park, the current world champion, touched in 3:41.86. Zhang Lin of China earned his country’s first swimming medal of the games, claiming silver in 3:42.78. American Larsen Jensen took the bronze in 3:42.78.

Favored Aussie Grant Hackett, who was in the lead off the blocks, struggled home in sixth.

Auto racing

Dixon can’t be stopped in IndyCar

Aussie earns his sixth win of the season, see Page C4