Rogers Cup: Naomi Osaka back on top of world rankings after Karolina Pliskova loses
Naomi Osaka will return to the top of the women's tennis world rankings after Karolina Pliskova lost in the quarter-finals of the Rogers Cup in Toronto.
Pliskova, number one for eight weeks in 2017, needed to win the tournament to regain top spot but lost 6-0 2-6 6-4 to Canadian teenager Bianca Andreescu.
Ashleigh Barty replaced Osaka at the top in June, but the Australian's run ended with her loss in round two.
Osaka plays 23-time Grand Slam singles champion Serena Williams on Saturday.
Their quarter-final will be their first meeting since last year's US Open final when Williams argued with the umpire late in the match and Osaka was awarded a game as a penalty on her way to winning a first Grand Slam title.
Andreescu, 19, is currently 22nd in the rankings and will play Sofia Kenin in the semi-finals after the American defeated Ukrainian sixth seed Elina Svitolina 7-6 (7-2) 6-4.
Naomi Osaka was in tears after her US Open win over Serena Williams as fans unhappy with the officials booed at the start of the trophy presentation ceremony