Jelena Jankovic moved closer to her first title in more than two years without hitting a ball on Thursday.
Jankovic received a walkover into the Aegon Classic quarterfinals when Casey Dellacqua withdrew with a stomach ailment.
The 22nd-ranked Jankovic is using the grass-court event as a tuneup for Wimbledon after being sidelined by a thigh injury in February.
"But at least I am progressing," she said. "I am good and healthy and finally getting some form, but it's really important that I keep my body in good shape. I have a new team, and I've been staying strong, so now I really want to take it to another level."
Zheng Jie, the only Chinese player to reach the singles semifinals at Wimbledon, will return to the top 30 rankings after defeating Andrea Hlavackova 6-4, 6-1 on the breezy court.
"It was not at all easy and I was pleased with the way I coped, even though I am a little bit tired," Zheng said after playing two qualifying matches and three tournament matches, along with doubles.
Zheng will face Roberta Vinci, the fourth-seeded Italian who overcame British wild-card Heather Watson, 6-3, 4-6, 6-1.
The condition of the courts has been criticized, with Iveta Benesova calling them "unplayable" and saying she "won't be back" after he loss.
Laura Robson, the former Wimbledon junior champion from Britain, noted "my back garden is better than this."