Elena Rybakina retired from her quarter-final against Iga Swiatek at the Cincinnati Open due to an ankle injury. The No 2-ranked Rybakina was trailing 4-1 when she took a medical timeout and retired moments later. With top seed Aryna Sabalenka losing to Sara Bejlek, Rybakina could have risen to No 1 in the rankings by reaching the final.

Defending champion Iga Swiatek has reached at least the semi-finals in each of her last four Cincinnati appearances. She will face American Jessica Pegula in the last four after Pegula came through a fightback from Amanda Anisimova to claim a 6-4 2-6 7-6(4) victory. Swiatek expressed sympathy for Rybakina, hoping the injury is not serious ahead of the US Open.

In the men's draw, seventh seed Flavio Cobolli recovered from a poor start to beat Tommy Paul 2-6 6-3 6-4 and reach his first ATP Masters 1000 semi-final. He will play Arthur Fils for a place in the final after Fils defeated Argentina's Thiago Agustin Tirante 6-3 6-2. The US Open begins August 30 live on Sky Sports.