Andreeva will next face Ukrainian Marta Kostyuk, the No 10 seed, who defeated American wildcard Sloane Stephens 7-5, 7-5. It is a rematch of their Roland Garros semifinal in June, when Andreeva beat Kostyuk 6-1, 6-3 en route to her first Grand Slam final.
The win was Andreeva’s, 19-year-old, 54th at WTA 1000 level, moving her past Coco Gauff’s 53 for the most by any teenager since the format was introduced in 2009. It also carried broader significance for a player still working her way back to form: her first back-to-back wins since Roland Garros, and her first appearance in any tournament’s last 16 since June. It is her fifth WTA 1000 last-16 of the year and her 41st win of the season overall.
Tjen raised her level sharply in the second set, forcing a tiebreak that Andreeva edged 7-5 to close out the match. Andreeva had reached this round by beating Ukrainian Oleksandra Oliynykova 6-1, 6-0 in the previous round, while Tjen, ranked No 37, got past Swiss Viktorija Golubic 7-6 (8), 5-7, 7-5.
Cincinnati WTA 1000, 3rd Round (Round of 32)
A. Sabalenka (1) vs X. Wang
S. Bejlek vs E. Alexandrova (16)
M. Keys (19) d. K. Siniakova (33): 6-1, 6-3
X. Wang d. E. Svitolina (8): W.O.
C. Gauff (4) vs A. Li (28); 6-1, 7-6
M. Bouzkova (22) vs I. Jovic (15)
M. Kostyuk (10) d. S. Stephens: 7-5, 7-5
M. Andreeva (5) d. J. Tjen (32): 6-1, 7-6
L. Noskova (6) d. O. Tauson (27): 7-6, 6-2
A. Anisimova (9) d. A. Eala (17): 4-6, 6-4, 6-2
S. Cirstea (16) vs A. Kalinskaya (19), 6-7, 6-1, 5-0, ret.
J. Pegula (3) d. E. Navarro (25): 7-5, 6-2
I. Swiatek (7) vs M. Sakkari (29): 4-6, 6-1, 6-1
D. Perry d. L. Boisson: 4-6, 6-4, 6-3
D. Shnaider (14) vs M. Chwalinska (19): 6-2, 7-6
E. Rybakina (2) vs Frech: 6-4, 7-4