South Africa's Chad le Clos reacts after winning the men's 200m butterfly final during the 2012 Olympic Games at the Aquatics Centre in London.

London - South Africa's Chad le Clos cried tears of joy after ending Michael Phelps' 200m butterfly reign at the Olympics on Tuesday.

Le Clos, third at the final turn, relentlessly tracked in Phelps and pipped him with a last-gasp surge to take the win in 1min 52.96sec.

Phelps, who had led at every turn in a quest to become the first man to win the same Olympic swimming event at three successive Games, was just five-hundredths of a second back in 1:53.01.

Phelps' silver medal took him level with Soviet gymnast Larisa Latynina as the most decorated Olympic athlete of all-time with 18 medals, which he subsequently bettered in America's 4x200m freestyle relay win later in the day.

It was an emotional visit to the podium for 20-year-old Le Clos.

Tears welled in his eyes as the South African national anthem was played as he stood beside his long-time hero Phelps and Japanese bronze medallist Takeshi Matsuda.

It was South Africa's second gold medal in the pool after Cameron van der Burgh's win in the 100m breaststroke.

“This is a dream of mine, I have always said Michael Phelps was my hero,” le Clos said.

“I wanted to be in the final for my main event, I achieved that goal and my coach said you have done all you have to do.

“But I just remember sitting in the call room thinking that Michael Phelps has never lost this race for 10 years in international meets.

“I remember turning in the last 50 and just looking at him underwater and realising this is my hero, it's crazy.

“I can't describe how I felt. In the last 25 metres I can't explain what came over me.”

Phelps had been untouchable in the 200m butterfly at major events. He owns the four fastest times in history and his world record of 1min 51.51sec is more than one second faster than the second-best performer in history.

Le Clos added that he had been receiving plenty of support from South Africa.

“I am really proud I had the nation behind me and after Cameron's win, it has lifted up the sport,” he said.

“I have been getting a lot of messages from back home. I am shocked by how many people seem to know me back home now.

“I'll have to try and defend my title in four years' time, but to beat Michael Phelps is something I have wanted my whole life, it is exactly what I have been dreaming of since I was 12.” - Sapa-AFP