Diana Shnaider advanced to the fourth tour-level quarterfinal of her career at the Thailand Open after Paula Badosa retired due to a low back injury trailing 6-2, 3-4.
Shnaider, 19, reached her first WTA final in Ningbo last September and reached a career-high of No.60 two weeks later, but fell out of the Top 100 this week after going 0-3 in this month's Australian swing.
In Hua Hin, she had already ousted No.1 seed Magda Linette in the first round, and backed it up with a near-flawless first set against Badosa. Shnaider fired return winners, passing shots and lobs to dominate the Spaniard.
Former World No.2 Badosa showed grit in the second set, fending off a break point in each of her first three service games en route to a 4-1 lead. But Shnaider reined in some of her loose errors to chip away at the lead, and won the best point of the match in the final game with some outstanding defensive work.
Badosa, who was sidelined for six months last year due to a back injury and only returned to action three weeks ago, began to visibily struggle towards the end of that game, and was unable to continue.
Shnaider will play Dalma Galfi next. The No.137-ranked Hungarian qualifier edged out No.5 seed Wang Xiyu 6-4, 3-6, 7-5 to reach her third career WTA quarterfinal (following Budapest 2021 and Linz 2023), and first on outdoor hard courts.
Highlights: Galfi d. Wang Xiyu | Putintseva d. Golubic
Two seeded players rounded out Wednesday's action by booking their spots in the last eight. No.3 Wang Xinyu defeated Nao Hibino 7-5, 6-4 and will next play No.7 seed Yulia Putintseva, who came through 7-6(0), 7-6(1) against Viktorija Golubic. Putintseva came from 3-1 down in the first set, saving two set points, to claim her first win in three meetings with the Swiss player.