Iga Swiatek advanced to the Cincinnati Open semi-finals after Elena Rybakina retired from their quarter-final with a left ankle injury on Friday, ending her bid to displace Aryna Sabalenka at the top of the WTA rankings. Rybakina, who managed just five games before withdrawing, needed to reach the final to overtake Sabalenka, who suffered a surprise fourth-round defeat to Sara Bejlek on Wednesday. Sabalenka will now remain world number one heading into the US Open, which begins on 30 August.
Swiatek, who is bidding to become only the second woman since 2004 to defend a Cincinnati title, faces home favourite Jessica Pegula in the semi-finals.
In the men's draw, Flavio Cobolli reached his first Masters 1000 semi-final by defeating Tommy Paul 2-6 6-3 6-4, while Arthur Fils beat Thiago Agustin Tirante in straight sets.