Singapore's Joseph Schooling poses with his gold medal on the podium of the Men's 100m Butterfly Final during the swimming event at the Rio 2016 Olympic Games at the Olympic Aquatics Stadium in Rio de Janeiro on August 12, 2016.

In just one performance, Singapore's Joseph Schooling beat swimming great Michael Phelps, took home his city state's first Olympic gold medal and became an instant millionaire.

Known at home for smashing national records and taking multiple titles in regional competitions, Schooling had held the hopes of Singapore, a Southeast Asian island nation of less than six million, which had only won two silvers and two bronzes since it joined the Olympic fold in 1948.

"Its been a hard road, I've done something that no one in our country has done before. I've received a lot of support and that's phenomenal," Schooling told reporters.

"It's been a tough road, I'm not going to lie, the first guy through the wall, it's always bloody," he said.

Watched by his mother and president Tony Tan in the stands, the 21-year-old beat Phelps, South Africa's Chad Le Clos and Hungary's Laszlo Cseh in the 100 metres butterfly final on Friday, to grab the gold while the others completed a remarkable three-way dead-heat for silver.

Singapore has spent millions trying to win more medals at the Olympics, including offering a Foreign Sports Talent programme which grants promising foreign athletes citizenship, as well as a S$1 million ($743,494.42) prize for gold medals.

Schooling left the country at 14 to train in the United States and now studies at the University of Texas in Austin, whose programme is led by two-time U.S. Olympic men's head coach Eddie Reese.