Defending champion Radhika Tulpule caused a major upset, toppling top-seed Rushmi Chakravarti in an absorbing three-setter, while German qualifier Varana Marie Beller crushed eighth seed Sonal Phadke of Mumbai in straight sets, to move into the quarter-finals of the NECC-ITF women's tennis tournament, in Pune, on Wednesday.

Radhika took just one hour and 33 minutes to end the challenge of the top seed, winning 6-3, 1-6, 6-3 to earn a spot opposite Ukraine's Kateryna Bondarenko, who had earlier ended Delhi girl Ankita Bhambri's challenge at 6-1, 6-4.

Bondarenko had crushed Tulpule in straight sets in last week's tournament.

Varana Marie Beller beat  Phadke 6-1, 6-2.

In other matches, Akgul Amanmuradova of Uzbekistan and third-seed Suchhanan Viratprasert of Thailand gave their respective Indian challengers Preeti Rao and Megha Vakharia a thrashing while cruising into the quarter-finals.

Second seed Jennifer Schmidt of Austria overcame a stomach upset to snuff out Mumbai lass Megha Vakharia's challenge, winning 0-6, 6-4, 6-4.

She will take on sixth seed Sania Mirza, who crushed current national champion and southpaw Isha Lakhani.

Earlier, the Radhika-Rushmi clash, contrary to expectations, failed to rise up to any appreciable levels. Radhika started off in a strong fashion. Using her forehand to good effect, she grabbed the chances that came her way to break her opponent. But Rushmi came up with two big serves to stave off the break-point and hold her serve. She, however, cracked under pressure and gave the first set to Radhika on a platter.

In the second set, Rushmi broke her opponent's serve in the second game itself and held to go up 3-0. With another break she consolidated her position to win the set and level the score one-all. Radhika came right on top in the decider and produced some competitive play to go up 3-1. However, she suffered a momentary lapse, allowing Rushmi to pull back and level the score at 3-3.

With some forceful shots on both sides of the flank, Radhika held her serve to lead 4-3, and then turned on the heat with some good returns. A controversial decision at 30-30 saw Rushmi lose her composure and her serve on the next point. Thereafter, there was no no looking back for Radhika, who closed out the next game on her second match-point.

Results (pre-quarter-finals): Sania Mirza (Ind) beat Isha Lakhani (Ind) 6-0, 6-1; Radhika Tulpule (Ind) beat Rushmi Chakravarti (Ind) 6-3, 1-6, 6-3; Kateryna Bondarenko (UKR) beat Ankita Bhambri (Ind) 6-1, 6-4; Akgul Amanmuradova (UZB) beat Preeti Rao (Ind) 6-1, 6-1; Jennifer Schmidt (AUT) beat Megha Vakharia (Ind) 0-6, 6-4, 6-4; Suchanan Viratprasert (Thai) beat Pemra Ozgen (Tur) 6-1, 6-1; Varana Marie Beller (Ger) beat Sonal Phadke (Ind) 6-1, 6-2; Ipek Senoglu (Tur) beat Krushmi Chheda (Ind) 6-1, 6-4.

Doubles: Ankita Bhambri/Isha Lakhani bt Kartiki Bhat/Samrita Sekhar 6-0, 6-4; Sania Mirza/Radhika Tulpule bt Liza Pereira/Keiko Tameishi 6-3, 6-2; Kateryna Bondarenko/Akgul Amanmuradova bt Rushmi Chakravarti/Suchanan Viratprasert 6-4, 6-3; Shruti Dhawan/Sheetal Gautam bt Sanaa Bhambri/Iciri Rai 6-1, 7-5.