Former tennis player Ashleigh Barty has revealed she had made the decision to retire before her victory at the Australian Open in January.

Barty shocked the world of sport when she announced her retirement last month. The 25-year-old revealed she was “absolutely spent” and “so ready” to step away from tennis.

She left the sport as the women’s world number one, a spot she first rose to in June 2019 and held since September 2019.

Barty earned three Grand Slam titles during her career, the most recent in January at the Australian Open.

In an interview with WTA Insider, the star revealed she already knew during the tournament that it would be her last.

"Playing the Australian summer was a really special opportunity for me to give it one last crack of playing at home and doing something no Aussie had done in over 40 years," Barty said.

"It was a really exciting opportunity for me. I just wanted to go out there, one last crack, no regrets, just enjoy the moment and see what happens.

"I think probably after the second round at the Australian Open, I sat down with my team and there was a moment for me where I was like, 'You know what, this is the last one. This is the last Australian Open.'

"Just really enjoy it, embrace it, take it for what it is, and stay super present in every moment because I'm never going to get that moment back again."

Barty’s coach Craig Tyzzer confirmed his mentee had been losing motivation in recent months, and disclosed the tennis star had even been considering retirement after her first Grand Slam win at the French Open in 2019.

"Once we got to the Olympics it hit home for me that there wasn't much left in her," he said. "The motivation wasn't there except when she played doubles with Storm [Sanders] and mixed with John Peers.

“Her singles really went by the wayside. I really felt like she climbed to where she needed to get to and it was going to be a hard slog to keep her involved. So I sort of felt it was coming.

"Even after her first Grand Slam at the French, I had actually prepared this speech about how profound this was going to be and what it meant for her. And her first words to me were 'Can I retire now?'"

Barty has stepped back from tennis before, calling time on her career in the sport after the 2014 US Open.

Still just a teenager, she chose to play professional cricket for the WBBL team Brisbane Heat instead, before returning to tennis in 2016.

This time around, Barty has made it clear that her “future lies elsewhere”. She has been seen playing golf, and recently announced plans for a series of children’s books.