Coco Gauff reached the quarter-finals of the China Open after Naomi Osaka retired with a back injury in Beijing.

This was a much-anticipated fifth meeting between two of the WTA Tour’s biggest stars – and a first since 2022 – and Gauff had just levelled at one-set all when Osaka, who received medical treatment early in the contest, shook hands.

Gauff helped carry Osaka’s bags off the court and then said: “It was a good match up until this point. I wish Naomi a speedy recovery. No one wants to win a match like this, especially one-set all.

“Overall I tried my best. It wasn’t my best tennis.”

It had been an encouraging week for Osaka, who was playing her first tournament under new coach Patrick Mouratoglou, and she was the better player for most of the two sets.

The Japanese star was within sight of victory when she broke the Gauff serve to lead 6-3 4-3 but she lost the next three games before calling it a day.

Zhang Shuai of China celebrates after winning a point against Magdalena Frech of Poland
Zhang Shuai (pictured) recorded a 6-4 6-2 win over Magdalena Frech (Achmad Ibrahim/AP)

Fourth seed Gauff will next face Ukrainian qualifier Yuliia Starodubtseva, who continued her brilliant run by defeating 10th seed Anna Kalinskaya 7-5 6-0.

Chinese wild card Zhang Shuai’s remarkable week also continued with the veteran, who came into the tournament having lost 24 singles matches in a row, making it four victories in succession with a 6-4 6-2 win over Magdalena Frech.

In the last eight she will take on 15th seed Paula Badosa, who upset US Open finalist Jessica Pegula 6-4 6-0.