Coco Gauff gets past injured Naomi Osaka in Beijing

Fourth-seeded Coco Gauff advanced to the quarterfinals of the China Open on Tuesday when Japan's Naomi Osaka retired before the third set in Beijing with a lower back injury.

Osaka won the first set 6-3 and was up a break leading 4-3 in the second set before losing the final three games and promptly retiring.

"I'm sorry," Gauff said to Osaka after sharing a hug at midcourt. "It's great to have you back."

Gauff, who took a 3-2 lead in their head-to-head series, helped the four-time Grand Slam winner carry her bags off the court.

"I wasn't sure if it was her hip or back, I just knew that toward the end she could barely jump on her serve," Gauff said, "so I knew that it was something that, in the moment, was probably bad but hopefully it's something that's not a long-term thing."

Gauff said she was surprised to have the match end so abruptly.

"Toward the end of the second set, I really saw it was hampering her movement a lot," Gauff said. "Even if you saw that last point, I was just trying to keep the ball in because I knew what was going on. But I didn't expect her to retire at that moment, honestly."

Gauff balanced six aces with six double faults and saved only one of six break points in the 88-minute match. She will face Ukrainian qualifier Yuliia Starodubtseva for a spot in the WTA 1000 event's semifinals. Starodubtseva defeated 10th-seeded Anna Kalinskaya of Russia 7-5, 6-0.

No. 15 seed Paula Badosa of Spain smashed No. 2 Jessica Pegula 6-4, 6-0 in just 64 minutes, her first victory in four meetings with the 2024 U.S. Open finalist.

Badosa trailed 3-1 in the opening set before winning 11 of the last 12 games, including eight in a row, to finish the match.

"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 after the match. "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."

Badosa's quarterfinal opponent will be China's Shuai Zhang, a 6-4, 6-2 winner against No. 23 seed Magdalena Frech of Poland. Zhang converted six of 12 break chances and has yet to lose a set in the tournament.

--Field Level Media