Magnificent seven: Phelps equals Spitz's Olympic record in dramatic style

Phelps trailed the Serbian swimmer for the whole race but somehow managed to touch just 0.01 secs in front to draw level with Spitz's record, set in Munich in 1972.

However, controversy followed the race, after Serbia lodged a protest over the result at the Water Cube.

Making a splash: Phelps celebrates his last-gasp victory over Cavic

The American trailed Serbian swimmer Milorad Cavic for the whole race and was well behind with just 15m to go but he finished like a train to prevail by just 0.01 seconds.

However, video footage on who touched first proved inconclusive, with some angles even suggesting Phelps was not ahead at the wall.

Serbia lodged a written protest but after officials reviewed footage and the electronic timing systems they declared themselves satisfied with the result.

The Serbs, according to an official, were also placated having had the opportunity to access the same information available to the referee.

Mixed emotions: An elated Phelps (right), whiile Cavic is stunned

The American set a new Olympic record in the process, touching in 50.58 secs with Australia's Andrew Lauterstein finishing third and world record holder Ian Crocker in fourth.

Michael Phelps equalled Mark Spitz's record haul of seven gold medals at an Olympic Games with victory in the most dramatic fashion over Milorad Cavic in the 100m butterfly.

'Beforehand, Bob (Bowman, Phelps' coach) said it would be good for me if I lost,' said Phelps.

'When he said that I was fired up. I said "I'm going to go for it" and when I saw that finish I said "wow". I had no idea the race was that close.

'When I took that last stroke I thought I had lost the race there, but it turns out that was the difference. I'm just lost for words.'