As Michael Phelps had an easy birthday Monday, Katie Hoff became the first swimmer to qualify for two spots in the Beijing Olympics.

Phelps, the American swimmer who turned 23 on Monday, broke his own world record in the 400m individual medley Sunday night at the U.S. Olympic swimming trials in Omaha, Neb.

The Baltimore native, who won eight Olympic medals -- six golds -- at the 2004 Athens Games, finished his first event at the trials in 4 minutes, 5.25 seconds. He held off rival Ryan Lochte for the victory. Lochte also finished under Phelps' old world-record time of 4:06.22, finishing in 4:06.08.

Phelps wasn't the only American to set a world record Sunday. Katie Hoff, whom Phelps used to train with in Baltimore before moving to Ann Arbor, Mich., broke the women's 400m IM record when she finished in 4:31.12. Australia's Stephanie Rice previously held the record of 4:31.46.

The teenage Hoff continued her pool exploits with a victory in the 400m freestyle Monday night.

Phelps, who is trying to break Mark Spitz' record of seven gold medals at a single Olympics, amended his trials agenda Sunday night. The American scratched the 100m backstroke from his schedule, meaning he will have six more events to race in at trials.

Phelps was back in the pool Monday in the men's 200m freestyle, an event he earned the bronze medal in at the Athens Olympics. Paired in the same heat as Lochte in the morning's prelims, Phelps won the heat as Lochte finished second.

Both Phelps and Lochte will go head-to-head again after winning spots in Tuesday's 200m freestyle finals.

Christine Magnuson won Monday's other final, claiming her first trip to the Olympics with a win in the 100m butterfly

Brendan Hansen had a big letdown in the 100m breaststroke, despite locking up a second straight trip to the Olympics. After just missing the world record in the semifinals, Hansen got off to a sluggish start and struggled home with a time of 59.93 -- good enough to win, but nearly a full second off the record of 59.1

World-record holder Aaron Peirsol advanced with the second-fastest time, beaten out by Randal Bal's effort of 53.09 that just missed Peirsol's mark of 52.98.

Also locking up expected spots on the team were two more second-place finishers, Mark Gangloff in the 100m breaststroke and Elaine Breeden in the 100m fly.

Coughlin Loses, Reclaims WR

Natalie Coughlin watched Hayley McGregory break her world-record mark in the 100m backstroke, only to reclaim the record just minutes later.

McGregory finished first in 59.15, bettering Coughlin's mark of 59.21 set Feb. 17. McGregory had barely climbed out of the pool before Coughlin got in and bettered the mark by finishing in 59.03.

Their efforts made Coughlin and McGregory the two leading qualifiers for the evening semifinals.