Clijsters won the US Open in 2005, 2009 and 2010, and the Australian Open in 2011. She initially retired in 2007 aged 23, making a return two years later after having her first child to win her second US Open, then hanging up her racquet again after the 2012 US Open. In a 51-second video on social media she asks: "Could I be a loving mum to three kids, and the best tennis player I can possibly be? "Let's do this. Let's come back one more time. See you in 2020."
Her return next season was warmly welcomed by WTA chairman Steve Simon. "Kim Clijsters ranks among the greats of the game and her return to the Tour is exciting news for the WTA family and tennis fans around the world," he said. Clijsters made her WTA debut aged 15 at Antwerp in 1999. She has 41 singles titles, and is the only mother to top the WTA charts since computer rankings began in 1975. Despite her lengthy time out she still ranks third among active players in terms of tournament success behind the Williams sisters - Serena with 72 titles and Venus with 49.