Singapore's only Olympic champion Schooling announces retirement. GETTY IMAGES

Joseph Schooling, the only athlete to beat Michael Phelps to win Singapore's first and only Olympic gold medal at Rio 2016, has announced his retirement from competitive swimming.

Schooling announced his retirement on social media, eight years after he stunned the world with a remarkable victory over American legend Michael Phelps in the 100m butterfly, setting the event's Olympic record of 50.39 seconds - later beaten by Caeleb Dressel at Tokyo 2020. 

"Today is the start of a new chapter. I am retiring from competitive swimming. I am filled with gratitude for all the experiences swimming has brought to my life," the 28-year-old said on Instagram. After winning gold medals in the 50m and 100m butterfly at the 2018 Asian Games in Jakarta, Schooling's career began to decline when she failed to qualify for the same event at Tokyo 2020. "The wins have been exhilarating, the losses humbling and together they have created a resilience in me that I will carry forward into my next chapter," Schooling said.

In an interview with the Straits Times newspaper, Schooling explained the reasons why he went from being an Olympic champion in 2016 to failing to qualify for Tokyo 2020. "My mistake was the complacency, thinking it's going to last forever because I'm so far ahead. Add to that ego, add to that pride. Add to that the 'I'll never be beaten' attitude. That's a recipe for complacency. That's one of the lessons I've learnt," says Schooling.

Problems came into Schooling's life when he admitted to taking cannabis overseas. Singapore has strict drug laws. Citizens can face up to 10 years in prison for what Schooling did. Schooling received a warning and underwent six months of supervised urine testing. He also lost the eligibility for leave during his military service for training or competing.

Schooling, the only athlete to beat Michael Phelps at Rio 2016 - the American swimmer competed in six events - is bidding farewell to competitive swimming, announcing his plans to work with two venture capital partners focused on "health and wellness, technology and sustainability", while also expressing his intention to play more golf. "While I am stepping away from competition, swimming will forever be a part of who I am. It has given me a platform to inspire others to chase their dreams, no matter the odds.

"I am excited to explore new passions, take on new challenges and see where this next phase of my life takes me. Thank you to my supporters for being with me every step of the way. I hope you will join me as I embark on this new adventure," he concluded.