Vashist upset fifth-seeded opponent Salvador Banderias of Portugal 6-1 6-3, while Shivani shocked third seed Snehal Mane 6-0 6-7(5) 6-1 in a two-hour battle between two local players at the MSLTA School of Tennis in Mhalunge Balewadi.
In other matches featuring Indians, Siddhant Banthia registered a 6-3 6-3 win over Anurag Nenwani, Udayan Bhakar was given tough moments before winning 4-6 6-4 6-3 against Sanil Jagtiani, while seventh-seeded Alex Solanki outplayed Irakali Metreveli of Geogia 6-1 6-2.
Top-seeded world no 83, Robert Wrzesinski of Lithuania , fourth-seeded Finn Bass of Britian and eighth-seeded Charles Robert of Thailand were the other boys to make it to the last eight.
In the girls' section, second-seeded Mahak Jain of India outplayed Russian Anna Solovyeva (RUS) 6-2 6-4, while fourth- seeded Akanksha Bhan went through a harrowing time before getting past compatriot Shivani Amineni 3-6 6-3 7-5 to enter the last eight.
Results (2nd round): Boys singles: Robert Wrzesinski (LTU,1) bt Kabir Manrai 6-1 6-3; Siddhant Banthia bt Anurag Nenwani 6-3 6-3; Finn Bass (GBR,4) bt Rishi Reddy 6-1, 6-2; Charles Roberts (Tha,8) bt Param Pun 6-3 6-1; Alex Solanki (7) bt Irakali Metreveli (Geo) 6-1 6-2; Udayan Bhakar bt Sanil Jagtiani 4-6 6-4 6-3; Aditya Vashist bt Salvador Banderias (Por,5) 6-1 6-3; Vashisht Cheruku (2) bt Nikoloz Davlianidze (Geo) 6-3 6-2.