Singapore's gold medal winner Joseph Schooling in the men's 100-meter butterfly final during the swimming competitions at the 2016 Summer Olympics,in Rio de Janeiro, Brazil, Aug 12, 2016.[Photo/IC]

RIO DE JANEIRO - Joseph Schooling won Singapore's first gold medal of the Rio Olympics by ending Michael Phelps' hegemony in the 100m butterfly on Friday.

Schooling, 21, touched the wall in 50.39 seconds, 0.75sec ahead of Phelps at the Olympic Aquatics Stadium.

Phelps, South Africa's Chad le Clos, and Laszlo Cseh of Hungary tied for the silver in 51.14.

Phelps had won the gold medal in the event at the last three Olympic Games.

He was aiming for his second so-called four-peat of the Rio Games after securing his fourth consecutive Olympic 100m individual medley gold medal on Thursday.

It was just the third Olympic silver medal of Phelps' career. He has won a record 22 gold medals and two bronze medals.

China's Olympic newcomer Li Zhuhao clocked 51.26 to be ranked 5th.