Baltacha will be sole representative in the women's competition
Britain's Elena Baltacha reached the Aegon International quarter-finals with a 6-2 1-6 6-3 win over world number 24 Zheng Jie in Eastbourne.
Baltacha, 26, will next meet French Open runner-up Sam Stosur, who beat Daniela Hantuchova 6-3 3-6 6-4.
There was no such joy for fellow Briton Heather Watson, who lost 6-1 6-1 to world number 15 Victoria Azarenka.
Watson, 18, had won three qualifiers and beaten world number 48 Aleksandra Wozniak earlier in the week.
But Azarenka, of Belarus, proved too strong and saw off Watson in 59 minutes.
"Azarenka played really well, she hit hardly any errors," said Watson, the world number 344. "In both sets I won the second game but wasn't able to stick with her.
"I've learnt a lot, I'll try not to let it happen again, but it's been really, really good. It has really prepared me for Wimbledon, I wasn't nervous at all about any of my matches and I've really enjoyed it."
Watson, from Guernsey, will now turn her attention to Wimbledon, where she has a wildcard for the tournament.
Meanwhile, Baltacha was thrilled by her own performance against Zheng.
"It's an unbelievable win and I'm still trying to process it. I knew I had a chance today but I knew if I was going to take that chance I would have to play unbelievable tennis," said the Scot.
"I started the match really well and took full control, then she had the momentum in the second set and kind of ran away with it.
"I knew the first game of the third set was so important and she had a couple of break points but I held and just kept on going."
Her next opponent, third seed Stosur, was delighted with her victory over Hantuchova - her 300th career win.
"Daniela is a good player and we've had some close matches," stated Stosur. "Windy conditions were not easy today, it was tough to play your best. But we still had a good quality match.
"I made the semis here a few years ago and from then on grass started to feel good to me. The more matches I get on it, the better I feel.
"In my last two matches I've really been playing well and I've felt at my best. I hope I can play even better considering the year I've had."
I feel that my foot is holding up good and obviously those were my main concerns
Fifth seed Kim Clijsters thrashed Lucie Safarova of the Czech Republic 6-1 6-0 to book her place in the quarter-finals, and showed no sign of the foot injury that has disrupted her year.
"It was a good one, quick and perfect," said the Belgian, who is playing her first grass-court tournament for almost four years.
"I feel that I'm moving well. I feel that my foot is holding up good and obviously those were my main concerns, especially the foot, when I first got here."
Russia's Svetlana Kuznetsova took two hours and 30 minutes to overcome Romania's Sorana Cirstea 4-6 7-6 (8-6) 7-6 (7-5), while Nadia Petrova lost 6-2 6-0 to qualifier Ekaterina Makarova in an all-Russian contest.
Spain's Maria Jose Martinez Sanchez went through when Aravane Rezai of France retired at 6-2 3-0 down, and French eighth seed Marion Bartoli defeated Agnes Szavay of Hungary 3-6 6-4 6-4.