National Champion Ashutosh Singh shocked top seed Pavol Cervenak of Slovakia in straight sets to advance to the second round of the USD 15,000 ITF tennis event in Bellary, Karnataka, on Tuesday.
Singh pipped Cervenak, ranked 332nd on the ATP list, 6-3, 6-4 to set up a clash with compatriot Vijayant Malik, who got past Vignesh Peranamallur Chandrasekhar 6-0, 7-5.
Both Malik and Vignesh had both qualified for the main draw.
In another upset, Aditya Madkekar went down fighting 7-6 (9,) 6-7 (1), 6-3 against qualifier Shivang Mishra.
Mishra next faces another qualifier Serbian Robert Bleak, who rallied to stun eighth seed Alexy Kedriouk 4-6, 7-6 (5), 6-2.
Also advancing to the pre-quarterfinals was Sunil Kumar Sipaeya after beating Vijay Kannan 7-5, 6-7 (1), 7-5.
Curtains were drawn on Navdeep Singh's campaign as he lost to second seed Teodor-Dacian Craciun of Romania 3-6, 2-6.
Wild Card Yuki Bhambri also made an early exit after losing his first round tie to fifth seed Dekel Valtzer of Israel.