Baltacha, the Scottish no1, has always had a topsy-turvy career but brilliantly brushed aside world no108 Chang Kai-Chen of Chinese Tapei on grass for the second time in four days to earn a shot at a potential Centre Court appearance.
The British no2 dismissed Chang 7-5 6-2 on Saturday in 104 minutes to race to a showdown against the winner between former Junior Wimbledon champion Robson or Borthwick.
“Chang’s very tricky on grass because she’s doesn’t go away and can suddenly ping winners out of nowhere.
“I am delighted to get through, especially because it was very windy out. I have always loved playing in Eastbourne, which always helps, and the crowd were great today.”
British no6 Johanna Konta, based in Eastbourne, squeezed past her new compatriot Naomi Broady in a final set tiebreak 7-4 to earn a 3-6 6-1 7-6 success.
Former Australian citizen Konta, who splits her time between Eastbourne and her family in Hungary, admitted:
“It is tough playing against a fellow countrywoman because there is always that extra pressure, so I am just happy to have come out on top on that one.”