No problems for Phelps

Australian star Grant Hackett, who already won gold in the 400 free, was top qualifier at 1 minute, 47.88 seconds - keeping himself on track for a delayed showdown with the world's best swimmer.

Phelps won his heat and was second fastest overall at 1:48.53.

Hackett and Phelps were supposed to face off in the 400 free Sunday night, but the 20-year-old American stunningly failed to escape the morning preliminaries.

With Phelps out of the way and Ian Thorpe skipping the championships, Hackett finally won the 400 title that eluded him at the last three world championships, as well as the Athens Olympics.

Each time, Hackett finished second to Thorpe.

"I feel better than I did yesterday morning," Phelps said, managing a smile. "I just wanted to come into today and win my heat. That was the big goal."

Phelps did win a gold on the first day of swimming as part of the U.S. 400 free relay team, giving him a chance to match his seven-medal haul from the 2003 championships in Barcelona.

But his pursuit of eight medals - the total he piled up at the Athens Olympics, including six golds _ ended with a dismal performance in the 400 free.

"I'm starting to get back on track," said Phelps, who only managed the 18th-fastest time in the 400 prelims. "What happened yesterday, that's behind us."

Hackett is eager to go head-to-head with Phelps, adding the 200 to an already grueling program for a chance to swim twice against the American. Now, it will be their only meeting in an individual event.

"Coming out after last night, which was a big day, I was a little tired but I needed to back it up," Hackett said. "I felt comfortable in that heat. I didn't put out too much emotion and energy. It was great."

American Natalie Coughlin, who won five medals in Athens, was top qualifier in the 100 backstroke at 1:01.25, though far off her world record from three years ago. She was followed by Japan's Reiko Nakamura, while American Jeri Moss also advanced to the semifinals with the 13th-best time.

"It was exactly what I needed to do," Coughlin said. "I wanted a good swim and good turns. That's all I was focusing on."

Australian world record holder Leisel Jones led qualifying for the 100 breaststroke, posting a time of 1:07.26. The next two spots went to Jessica Hardy and Tara Kirk of the U.S.

"I would have liked to have gone slower than that," Jones said. "A 1:08 would have been good enough."