The shocking thing wasn't that Michael Phelps failed to win the 400-meter freestyle final on the opening day of the 2005 world swimming championships Sunday night. The stunner was that he wasn't even in the pool when the race was contested.

Phelps, who won eight medals at the 2004 Summer Games in Athens, swam so slowly in his morning heat that he did not qualify for the final at Jean-Drapeau Park, sending his first major meet since the Olympics to an inconceivably bad start.

Phelps's time of 3 minutes 50.53 seconds ranked 18th in the morning, nearly six seconds slower than that of Australian silver medal winner Grant Hackett -- who claimed the world title on Sunday night in 3:42.91 -- and more than 1.5 seconds slower than the eighth and final qualifier.

"He thinks it's pretty horrible," Phelps's coach, Bob Bowman, told reporters shortly after Phelps faded to seventh among eight swimmers despite beginning the final lap in third place. "That was his word, and it was correct. It's horrible."

Though Phelps, 20, added this race and the 100 free to his repertoire this season, substituting them for two events in which he holds world records (200 fly and 400 individual medley) as a way of stretching himself leading up to the 2008 Summer Games in Beijing, he was figured to challenge Hackett for the gold here given the adaptability and all-around excellence he has shown in dominating the sport for the last two years.

At last summer's Games, he won medals (six gold) in five individual events and three relays, a feat he intended to replicate here. At the 2003 world championships in Barcelona, he broke five world records.

"It didn't go the way I wanted it to start off," Phelps told reporters shortly after the race. "I'm pretty disappointed. I felt good in the warmup, and then in the race it wasn't there."

Phelps bounced back in Sunday night's final of the 4x100 freestyle relay, leading the United States to its first major international gold medal in the event since the 1998 world championships in Perth, Australia, and he seized upon that success to try to mute the morning's disappointment. He said he couldn't remember failing to advance to a final in any previous international meet.

"I was a little happier tonight than I was this morning," he said, flashing a huge smile moments after the race. "It's definitely a step up from this morning's swim."

Phelps, who trains with the University of Michigan swim team even though he is a professional and ineligible for NCAA meets, said he spent the day trying to forget about the 400, and he refused to be lured into an analysis of the result later, leaving his rivals guessing about whether he would be ready to come back strong the rest of the week.

"I don't know" what happened, he said Sunday night. "I guess I just wasn't prepared to swim that race and it showed. . . . Maybe I'm just not used to swimming that race."

Phelps's best time in the event came two years ago (3:46.73), and he hasn't swum it much since. But Hackett, who raced shortly after Phelps's elimination -- only the top eight swimmers advanced -- said he was so flabbergasted he could barely get out of the blocks.

"Obviously, I'm surprised," he said Sunday morning. "I spent the first 10 meters of the race thinking about it. What a big shock that was."

Phelps has hit a few bumps since the Olympics, when he established himself as one of the most successful Olympians of all-time. He pulled out of last fall's short-course world championships (swum in a 25-meter instead of 50 pool) because of a back injury that hampered his training. He pled no-contest to driving while intoxicated in Salisbury, Md., in November.

"Things can happen in the blink of an eye," Phelps said last week during a conference call. "Obviously my head wasn't on straight and I didn't have my goals locked in my mind."

Phelps will compete Monday in the qualifying heats and semifinals of the 200 free, an event in which he finished third behind Thorpe and Pieter Van Den Hoogenband at the Olympics (it was his only individual bronze).

"I don't think you can write off the whole meet because he had a bad prelim swim," Bowman said in the morning. "We'll have to see how he does tonight in the relay, how he does tomorrow in the 200, and then we'll know a lot more about where he stands -- whether this was just a bad swim or something else."

The relay suggested the former. Phelps put the United States in front with a first lap in 49.17 seconds that topped even Australian Michael Klim (49.75).

"Hopefully I'm in better shape for the 200 than I was for the 400," he said. "We'll see tomorrow."

"It didn't go the way I wanted it to start off," said six-time gold medalist Michael Phelps after a 7th-place finish in his 400M heat. "I guess I just wasn't prepared to swim that race and it showed," Michael Phelps said of his effort.