MELBOURNE, Australia (AP) – Michael Phelps stayed on track for a record gold-medal haul at the world championships, edging out American teammate Ian Crocker by 0.05 seconds to win the 100-meter butterfly Saturday night.

Mr. Phelps is 6-for-6 with two races remaining. His latest gold tied Australian Ian Thorpe’s record set at the 2001 worlds in Japan.

As the two-time defending champion and world record holder, Mr. Crocker was the one guy who could’ve stopped Mr. Phelps’ gold rush. But it didn’t happen.

Mr. Crocker was first at the turn, with Mr. Phelps third – the first time in four individual races that Mr. Phelps didn’t zoom to the lead. But he sure came home hard.

Mr. Phelps caught Mr. Crocker in the final furious strokes – touching in 50.77 seconds and joining his rival as the only men to break the 51-second barrier. Mr. Crocker hit the wall in 50.82. Albert Subirats of Venezuela took the bronze.

Mr. Crocker swam over to Mr. Phelps in lane six and shook his hand.

American Ben Wildman-Tobriner conquered swimming’s most chaotic 22 seconds, winning the 50 freestyle in an upset over more heralded teammate Cullen Jones and defending champion Roland Schoeman of South Africa.

Mr. Wildman-Tobriner touched in 21.88 seconds; Mr. Jones at 21.94 for the silver.

“It’s hard not to be disappointed when you’re kind of the favorite going in and you get second,” Mr. Jones said. “It does leave a sour taste in your mouth, but coming in second to your own teammate definitely softens the blow a little bit.”

Mr. Wildman-Tobriner was only sixth-fastest coming into the final, while Mr. Jones was second-fastest.

“There was zero pressure on me,” Mr. Wildman-Tobriner said. “Honestly, it’s not a surprise to me. Hitting the start well, which I have been struggling to do, I knew I would definitely have a good chance. When I hit the water, I felt it was right. It gets you fired up for rest of the lap.”

Mr. Jones gained major attention by winning the 50 free at the Pan Pacific championships in August (Mr. Wildman-Tobriner was fifth), and the black swimmer wanted a world title to further his goal of getting kids of all colors interested in the sport.

“Anything I do, as long as I’m trying to promote diversity in swimming, I think is going to help no matter what,” Mr. Jones said. “I just hope this is not a trend. At world short course, I got silver. Here I got silver. Hopefully, at the Olympics I get gold.”

Stefan Nystrand of Sweden earned the bronze. Schoeman faded to seventh.

Mr. Wildman-Tobriner goes by a combination of his mother’s maiden name and his father’s name. The 22-year-old Stanford swimmer’s first international gold medal came at the 2005 worlds, when he swam on the 400 freestyle relay in the morning. He also swam preliminaries of the 400 free here, earning a gold.

Margaret Hoelzer of the United States ended her runner-up streak in the women’s 200 backstroke, winning with the second-fastest time ever – 2 minutes, 7.16 seconds.

The 23-year-old former Auburn swimmer had finished second at the 2003 and ’05 worlds, where she was beaten by Kirsty Coventry of Zimbabwe.

Ms. Coventry led the first 100 meters before Hoelzer edged ahead at the third turn. Coventry settled for silver in 2:07.54. Reiko Nakamura of Japan was third.

Therese Alshammar of Sweden won the women’s 50 butterfly – a non-Olympic event – in 25.91 seconds for her first world title at age 29.

Danni Miatke of Australia took the silver. Inge Dekker of the Netherlands earned the bronze. American Rachel Komisarz was fifth.