British number one Johanna Konta has pulled out of the Canadian Open with a knee injury.
The 30-year-old was set to face 15th seed Coco Gauff in the third round, with the American now advancing to the quarter-finals by walkover.
The event in Montreal was Konta’s first since the Nottingham Open in June.
She pulled out of Wimbledon when a member of her team tested positive for Covid-19, then missed the Olympics after contracting the virus herself.
On her return, Konta got through the opening round, as China’s Zhang Shuai won the first set of their match before retiring with a leg injury when 5-2 down in the second.
Konta then fought back from a set down to defeat third seed Elina Svitolina to set up the third-round meeting with Gauff.
Canadian second seed Bianca Andreescu called two medical timeouts for injuries as she lost to Tunisia’s Ons Jabeur in the third round.
Jabeur came from a set down to beat Andreescu 6-7 (5-7) 6-4 6-1 and will face the USA’s Jessica Pegula in the quarter-final.
At the men’s tournament, being held in Toronto, the highest men’s seeds remaining both progressed to the quarter-finals.
Number three seed Stefanos Tsitsipas celebrated his 23rd birthday in style with a 6-3 6-2 win over Tokyo 2020 silver medallist Karen Khachanov, before being presented with a birthday cake.
He was joined in the quarter-finals by top seed Daniil Medvedev from Russia, who beat Australian qualifier James Duckworth 6-2 6-4.