Coco Gauff progressed to the quarter-finals of the China Open after Naomi Osaka was forced to withdraw from their blockbuster clash with the match tied at one set all in Beijing.

Osaka led by a set and a break before fourth-seed Gauff battled back to level things up at 3-6 6-4 and force a decider.

However, the former world No. 1 was unable to continue, and her American opponent helped carry her bags off the court after 87 intense minutes of competition.

Osaka’s withdrawal sent Gauff into the last eight for a second successive year, where she will face Ukrainian qualifier Yuliia Starodubtseva.

“It was a good match up until this point. I wish Naomi a speedy recovery, nobody wants to win a match like this, especially at one set all,” Gauff said on court. 

“I tried my best, it wasn’t my best tennis. It was one of those matches where you are trying your best each point.

“It’s cool to be back in the quarter-finals here in Beijing. I’ve been playing the late match every day, so maybe I’ll get sunshine in the next match. We’ll see what the schedule allows.”

Osaka’s withdrawal was an unfortunate ending to an otherwise gripping encounter.

After an early exchange of breaks, Osaka began to pull away, edging the majority of blistering baseline rallies and securing the break at 3-1 with a brilliant drop volley into acres of exposed court.  But Gauff broke back once more, restoring parity with a hold at 3-3 as a high-quality set of brutal power-hitting developed.

Osaka briefly had a medic on court after the fifth game and her back appeared to trouble her at times, moving gingerly at the changeovers, but she continued to pile pressure on Gauff, who had chances of her own to break again.

A double fault in the eighth game gave Osaka two break points and the four-time major winner was in control at the baseline, moving Gauff from side to side and forcing her to net.

Osaka looked cool and composed as she served for the set at 5-3, with both players producing some pacy, fierce hitting and Gauff fighting to stay in it, but she overcooked a return to concede the set in 36 minutes.

Gauff’s resolve was undented by going a set down, returning with a businesslike hold to 15, and she moved 2-0 up after a game showcasing the best of both players.

The high-quality baseline rallies continued, and both players mixed up their game, Gauff nicking the sideline with a brilliant backhand winner and delicately playing a gentle drop shot with Osaka marooned at the back of the court. Although Osaka expertly targeted Gauff’s vulnerable forehand wing, she netted to hand over an early break, and continued to look uncomfortable physically.

But as in the first set, the breaks continued, with both players struggling in two mammoth games. Gauff had seven game points across the two but could convert neither as Osaka levelled things up at 2-2, and momentum swung again at 3-3 as Gauff suffered a dismal service game littered with double faults to fall 4-3 behind.

The drama didn’t stop there: a first double fault by Osaka, at break point down, levelled things once more and sent Gauff on her way to a run of three consecutive games that wrapped up set two.

Gauff’s next opponent, world No. 115 Starodubtseva, continued her superb week by beating 10th seed Anna Kalinskaya 7-5 6-0.

The winner of their clash will be up against Paula Badosa or Shuai Zhang in the Beijing semi-finals.

Badosa dispatched US Open runner-up Jessica Pegula 6-4 6-0 to progress to the last eight, while home favourite Zhang toppled Magdalena Frech 6-4 6-2.

The Spanish player’s ruthless performance meant her win was wrapped up in just 64 minutes, after recovering from 3-1 down in the opening set to win 11 of the following 12 games.

“She’s one the of the players I never want to face – she’s very solid, hits very flat, changes very well direction, so I knew it was going to be tough,” Badosa said.  

“Yesterday I prepared myself for a battle, but I think today everything worked pretty well. 

“I was moving well, my backhand, my forehand was there today, and I fought. Every point was very important for me, especially against Jessica, because she can come back at any moment. I’m really happy for this win, honestly.”