Japan's Kurumi Nara dispatched eighth-seeded Jelena Jankovic 6-7 (4), 7-5, 6-4 in the first round of the Taiwan Open in Taipei City on Tuesday.
Nara prevailed in a two-hour, 44-minute battle to move into the second round against China's Lin Zhu, who recorded a 6-3, 5-7, 6-4 victory over Poland's Magda Linette.
Nara recovered from the opening-set loss while Jankovic of Serbia said he was bothered by low back pain.
"Over time it was feeling worse and worse," Jankovic said after the match. "I tried and tried to fight, but in the end it wasn't good enough. I never enjoy being on court when I'm in pain."
The top three seeds all advanced in straight sets.
Top-seeded Elina Svitolina of the Ukraine rolled to a 6-0, 6-3 victory over Russia's Evgeniya Rodina; second-seeded Samantha Stosur posted a 6-2, 6-4 win over Danka Kovinic of Montenegro, and third-seeded Caroline Garcia of France was a 6-3, 6-2 winner over New Zealand's Marina Erakovic.