Number two seed Elise Mertens knocked out qualifier Anhelina Kalinina 2-6, 6-1, 6-2 to advance to the second round of the Linz Open on Wednesday.
Mertens, who reached the quarter-finals of the US Open for a second year in a row, lost the opening set in 43 minutes before Mertens raced to level up, saving a break point late on.
The Belgian then broke the 23-year-old in the fifth game of the third set at the third time of asking before breaking again to go 5-2 up. She won the match with the first of her three match points with an ace.
'It feels very special' - Osaka explains why WTA Miami is close to her heart
She will meet former world number two Vera Zvonareva in the second round, who beat teenager Marta Kostyuk in straight sets on Tuesday.
Number six seed and shock 2020 French Open semi-finalist Nadia Podoroska beat Irina-Camelia Begu in straight sets, breaking four times to win it 6-4, 6-4 in one hour and 45 minutes.
- When are the ATP Finals, who's playing and when is the draw?
- Henman rules out GB captaincy at ATP Cup
WEDNESDAY'S OTHER RESULTS
Aliaksandra Sasnovich (BLR) bt Jana Fett (CRO) 3-6, 6-1, 6-3
Oceane Dodin (Fra) (Q) bt Jil Belen Teichmann (SUI) (7) 1-6, 6-4, 6-2
Barbora Krejcikova (CZE) bt Greetje Minnen (BEL) 5-7, 7-6(7), 6-4
Veronika Kudermetova (RUS) (5) bt Barbara Haas (AUT) 6-0, 6-0
Ekaterina Alexandrova (RUS) (4) bt Varvara Gracheva (RUS) 7-5, 6-1
In-form Muguruza reaches Dubai final with win over Mertens
Azarenka clobbers Mertens to set up Serena showdown