BEIJING - Michael Phelps tied Mark Spitz for the most gold medals won at an Olympic Games, coming from behind to win his seventh gold of the Beijing Games the 100-metre butterfly.

It's the first time in Beijing that Phelps didn't set a world record en route to winning gold.

Phelps was well behind at the halfway point but swam a blistering final 50 metres to beat Serbia's Milorad Cavic by the slimmest of margins.

Phelps finished in an Olympic-record time of 50.58, while Cavic took silver in 50.59.

Australia's Andrew Lauterstein took bronze in 51.12.