Michael Phelps failed in his first bid to qualify for his first international meet since the London Games, finishing seventh Wednesday in the 100m freestyle at the US Swimming Championships.
Phelps, whose record 22 Olympic medals include an astonishing 18 golds, ended a near two-year retirement in April.
But his first attempt to take his comeback to a new level by qualifying for a major international meet -- the Pan Pacific Championships later this month -- fell flat.
He was last at the turn and couldn't find the last-lap speed needed, settling for seventh in 49.17sec.
Nathan Adrian, the 100m free Olympic gold medalist in London, won in 48.31sec.
Ryan Lochte, whose own collection of 11 Olympic medals includes five golds, stormed to second from lane eight in 48.96.