ROME (AP) - Michael Phelps was unconcerned about posting only the second fastest time in morning heats for the 200-meter freestyle at the world championships Monday.
Paul Biedermann of Germany beat the swimmer who won a record eight gold medals at last year's Beijing Olympics.
Phelps won the final heat, but Biedermann's time in the previous heat was faster.
"That's fine. I'll be in the first heat tonight," Phelps said, looking ahead to the evening semifinals.
Biedermann won the heats in 1 minute, 45.30 seconds. Swimming his first individual event, Phelps clocked 1:45.60, and Danila Izotov of Russia qualified third in 1:45.86.
Phelps holds the world record of 1:42.96 set at last year's Beijing Olympics.
Olympic silver medalist Park Tae-hwan of South Korea qualified eighth, after missing the final of the event he won in Beijing - the 400 free.
Biedermann broke Ian Thorpe's seven-year-old 400 free world record Sunday.
Phelps also won his first gold on the opening day in the pool, swimming the leadoff leg for the Americans in the 400 free relay.
"That felt really good coming off the relay. It felt really controlled for a morning swim," Phelps said. "We noticed yesterday that all the guys were swimming faster in the morning, so you have to kind of step up in the morning."
Biedermann doesn't have any designs on beating Phelps when it counts - in Tuesday's final.
"I don't think it's going to be much of a duel at all," the German said. "He's a very good racer. I think he looked really relaxed this morning. From looking at the time he's in really great shape."
Still, Phelps was impressed with Biedermann's swim in the 400, one of six world records set Sunday in likely the last meet that 100 percent polyurethane bodysuits will be permitted.
"I still can't believe the 400 free got broken. I thought that was the best record on the book," Phelps said. "It was crazy to see that go, but people are swimming fast. You usually don't see that in a post-Olympic year, but it's good for the sport. It makes it more exciting."
In the women's 100-meter backstroke, Gemma Spofforth of Britain set a championship record with a time of 58.78, improving on American Natalie Coughlin's 59.44 from the last worlds in Melbourne, Australia two years ago.
Anastasia Zueva of Russia touched second in 59.01 and Olympic silver medalist Kirsty Coventry of Zimbabwe was third in 59.51.
Coventry holds the world record of 58.77.
Coughlin, the Olympic and defending world champion, is taking this year off.
Olympic silver medalist Rebecca Soni of the United States led the 100 breaststroke heats in a championship record 1:05.66. Leisel Jones held the previous mark of 1:05.72 set two years ago, and the Australian also holds the world record of 1:05.09, although she is sitting out these worlds.
Yuliya Efimova of Russia was second in 1:06.42 and Olympic bronze medalist Mirna Jukic of Austria was third in 1:06.58.