Sam Stosur had a premonition she was going to thrash Serena Williams to win the US Open crown

Australian tennis champion Sam Stosur reached the peak of her career in 2011 when she dethroned former Serena Williams to claim the US Open crown – and she has revealed she was almost certain they would win the night before the match would.

On Saturday, Stosur announced via Instagram that this year’s Australian Open will be her last professional tournament.

The 38-year-old also won seven mixed doubles and women’s major titles, but it was her underdog straight-set win over Williams that she will remain best known for.

“I don’t know what it was — the night before when I got into the finals, I just felt like I was going to win the next day,” Stosur told Weekend Today on Sunday.

“I mean, that’s a moment every athlete dreams of… being in the zone. Do anything you want to do. For whatever reason, it happened to me that day.’

Stosur (pictured celebrating with the trophy after winning the US Open crown) had an inexplicable feeling that she was going to make her best game against Serena Williams

The 38-year-old explained that she was “in the zone” as she was living every athlete’s dream on one of the biggest stages in tennis

The Queenslander passed Angelique Kerber, Nadia Petrova and Maria Kirilenko to secure a spot in the final before defeating her only major in singles to become the first Australian to triumph at Flushing Meadows since Margaret Court in 1973.

The former world No. 4 also dominated on the French clay, reaching the Final Four four times, including a loss in the 2010 decider.

Making her professional debut aged 15 in 1998, Stosur acknowledged that time “crept up on her” before announcing her retirement in an emotional social media post on Saturday night.

“I’m really grateful for the past year, but now I can do normal things at home — I’ll probably be the one who drops childcare or something,” she said.

The Queenslander also excelled in doubles on the tour, winning the 2005 Australian Open mixed titles with fellow Australian Scott Draper

Stosur will be looking to emulate her success at the 2005 Australian Open when she won the mixed doubles with compatriot Scott Draper.

The two defeated Liezel Huber and Kevin Ullyett in the final 6-2, 2-6. [10–6].

Stosur rose to career-high world rankings of No. 4 in singles and No. 1 in doubles in the 2000s.

Australia’s Matt Ebden will partner Stosur in mixed format this year, while France’s Alize Cornet will join the veteran in women’s doubles.

“Even though I made the decision to retire from the sport I absolutely love, a small part of me would be happy to continue playing forever,” Stosur wrote on Instagram.

“I’m so happy and grateful to have the opportunity to finish my favorite slam – my home slam – in front of my Australian fans, friends and family.”