The 21-year-old India No. 1 Ankita, the fourth seed, advanced into the quarter-finals with a hard-fought three-set victory over Thai qualifier Kamonwan Buayam, ranked 264 places below her on the WTA list, in a second round match at the Deccan Gymkhana.
Ahmedabad-born Ankita, ranked 294th currently, won 6-3 6-7(3) 6-1 by converting seven out of eleven chances to break her opponent's stronger serve. The Thai girl hit four aces but, in going all out, also committed 15 double faults.
Wild card Prarthana - who bagged the bronze medal with Sania Mirza in the women's doubles at the Incheon Asian Games a few months ago - went down in three sets after a fight against third seed Sofia Shapatova of Georgia.
The 25-year-old Tbilisi-born Sofia, who was ranked as high as 186 this September before slipping to her current place of 228, quelled the strong challenge of 20-year-old Maharashtra-born Prarthana - who committed 8 double faults - 6-4 6-7(4) 7-6(6).
Top seed Anastasia Vasylyeva of Ukraine, ranked 174th, also moved into the last eight after surviving some anxious moments against Japan's Ayaka Okuno, clinching the second round match 6-3 6-7(5) 7-5.
Other results: 6-K Dunne (GBR) beat D Papamichail (GRE) 6-2 6-4; M Frech (POL) beat Margarita Lazareva (RUS) 6-2 7-5; Ellen Allgurin (SWE) beat 8-Veronica Kapshay (UKR) 6-3 6-7(3) 6-1; Cristina Ene (ROU) beat Sviatlana Pirazhenka (BLR) 6-2 6-3.