Elena Rybakina was forced to retire injured during her Cincinnati Open quarter-final against Iga Swiatek, ending her bid to overtake Aryna Sabalenka as world number one. The Kazakh second seed had needed to reach the final to claim top spot after Sabalenka's shock fourth-round loss, but instead pulled up with a left ankle injury while trailing 4-1.

Rybakina managed just five games before calling for a medical timeout at 40-40 and quitting after one more point, saying she could not push off her serve and would have an MRI to assess the damage. Swiatek, who beat Rybakina in last week's Canadian Open final, advances to face Jessica Pegula and is chasing a Cincinnati title defence achieved by only Serena Williams since 2004. Elsewhere, Flavio Cobolli credited a sugar boost from M&M's for a comeback win over Tommy Paul, setting up a semi-final against Arthur Fils.