The first day of Olympic competition at the 2012 London Games included an epic showdown in the men’s 400-meter individual medley between swimming’s biggest stars – Americans Ryan Lochte and Michael Phelps.

Lochte, the defending world champion in the event, ended Phelps’ reign as the two-time defending Olympic champion and took gold in 4:05.18.  Thiago Pereira of Brazil was second and Japan’s Kosuke Hagino was third.

But the shocker of the event was Phelps, who finished fourth in 4:09.28.

Phelps swam the race from the outside lane 8 after a rare slow swim in the morning’s heat gave him the eighth fastest time at 4:13.33, narrowly qualifying him for the final. He was just .07 of a second faster than the ninth-placed swimmer, Laszlo Cseh, who took silver in the 400m IM behind Phelps at the 2008 Beijing Games.

Lochte eased into the final with the third fastest time in the morning session.

Phelps needs three medals in London to become the all-time leader in total Olympic medals. He entered London with 16 medals, including 14 gold.

Phelps etched his name in the swimming and Olympic record books in 2008 when he won all eight events he competed in to take home an unprecedented eight Olympic gold medals.

Lochte, a Florida native, has been the swimmer to beat since Beijing, winning five gold medals at the 2011 World Championships.

Lochte had Phelps’ number at Worlds, but Phelps edged Lochte at last month’s Olympic Trials. In what was called a cat-and-mouse game during the Trials, Lochte narrowly defeated Phelps in the 400m IM before Phelps hit the wall first in the 200m freestyle and 200m IM.

Phelps will be back in the pool Sunday in the men’s 4x100m relay.