Phelps clocked 4mins 05.22secs to break his previous mark of 4:06.22 and edge out Ryan Lochte.

The 22-year-old Phelps clocked the second-fastest time in the event's qualifying swim, finishing in 4:13.43.

Lochte, who holds the world record in the 200m backstroke, was the fastest qualifier in 4:13.38.

Katie Hoff quikcly followed Phelps' lead, winning the women's 400 metre individual medley in a world record 4:31.12secs.

Hoff erased Stephanie Rice's mark of 4:31.46 to qualify for the trip to Beijing alongside 15-year-old Elizabeth Beisel, who finished second.