In 1970, Court became the first woman during the Open era (and the second woman in history after Maureen Connolly) to win the singles Grand Slam (all four major tournaments in the same calendar year). She won 24 of those titles (11 in the Open era), a record that still stands. She also won 19 women's doubles and 21 mixed doubles titles, giving her a record 64 major titles overall. Her all surfaces (hard, clay, grass and carpet) singles career winning percentage of 91. 74 percent is the best of all time according to the Sporteology website. Her open era singles career winning percentage of 91. 37% (593–56) is unequalled, as is her Open Era winning percentage of 91. 7% (11–1) in Grand Slam finals. Her win-loss performance in all Grand Slam singles tournaments was 90. 12% (210–23). She was 95. 31% (61–3) at the Australian Open, 90. 38% (47–5) at the French Open, 85. 10% (51–9) at Wimbledon and 89. 47% (51–6) at the US Open. She also shares the Open era record for most Grand Slam singles titles as a mother with Kim Clijsters. In 1973 Court set the record for most titles won in a single Grand Slam event, with 11 Australian Open wins. This record was surpassed by Rafael Nadal on June 9, 2019 when he won his 12th French Open title.