Former world number one Venus Williams rolled into the Taiwan Open semi-finals with victory over Anastasija Sevastova on Friday.
Williams was tested early but the top seed was a class above as she won 7-5 6-2 in the quarter-finals.
The seven-time grand-slam winner - looking to claim her first WTA title since November - only served at 47 per cent but still did enough to advance after a little over an hour on court.
Awaiting Williams in the final four is third seed Yulia Putintseva.
Putintseva had just won the opening set 6-3 when Swiss opponent Stefanie Voegele retired in Taiwan.
Japanese second seed Misaki Doi moved within a victory of the final without taking to the court.
Countrywoman and seventh seed Kurumi Nara withdrew before a ball was hit.
Next up for Doi is Hsieh Su-wei, who accounted for Elizaveta Kulichkova 6-0 6-2 in just 52 minutes.