Phelps Sets World Record in 100-Meter Butterfly, Dara Torres, 42, Wins 50 Free

Torres has retired after so many Olympic Games -- only to return before the next -- that she has competed in just one previous world championships, the 1986 event in Madrid. There, she won a silver medal in the 400 freestyle relay.

In Beijing last summer, as Torres finished second in the 50 free and set the current American record, Phelps set -- or helped set -- world records in seven of his eight events. The only mark he missed came in the 100 fly, a race he nearly lost to Serbia's Milorad Serbia.

On Thursday, he easily beat Tyler McGill of Auburn University, who finished second in 51.06 and became the sixth-fastest man ever in the event . Backstroke specialist Aaron Peirsol claimed third in 51.30 seconds -- making him the 11th-fastest man ever.

Phelps, of course, is now first.

After Crocker beat Phelps by 1.25 seconds in the event at the 2005 world championships in Montreal, Phelps told his coach Bob Bowman he wanted to "put a bag over his head." Bowman told Phelps, he recalled, that he wanted to do the same.

"In the race Ian broke that record, that was the worst Michael had ever been beaten," Bowman said. "We both remember that. . . . That is an amazing record. That's why it stood the test of time."

Phelps credits his emphasis on speed events since he returned to the pool six months ago for allowing him to approach what had been such an elusive mark. Phelps said he has never trained the 100 fly harder, and he's also undertaken a far more rigorous weight-training regimen designed to build the upper-body strength he needs in sprint events.

"It's killed my body," he said. "There are days I can't pick anything up."

Phelps's previous best in the event was the 50.48 he swam a couple of weeks ago in Montreal.

"Everything I've done has been something I've wanted to do, and something I've dreamed of," Phelps said. "I would have liked to have gone eight for eight in Beijing, eight records and eight races. It feels good to have this one here."