Top seed Somdev Devvarman struggled past Ramkumar Ramanathan, who was troubled by cramps, but Yuki Bhambri made a fluent start with a straight set win in the USD 50,000 ATP Challenger event in Chennai.
Somdev, who was shocked by Ramkumar in the Chennai Open, yet again faced a stiff challenge from local boy, who countered India's number one player with his aggressive play, specially his fierce forehands.
Ramkumar saved eight of the 10 breakpoints he faced and succeeded in breaking Somdev once in the second set. However, it was difficult for him to match Somdev's fitness and after one hour and 53 minutes of battle of attrition, he was struggling to stand on his feet and retired from the first round contest.
Somdev came into the event after winning a marathon Davis Cup match against Ti Chen, but he fought with sheer intensity. His superior fitness and ability to hold nerves in pressure moments was key to Somdev's win.
Somdev will next face New Zealand's Michel Venus, who ousted local wild card Jeevan Nedunchezhiyan 6-7(3) 7-6(1) 6-1.
Meanwhile, Yuki Bhambri brushed aside the challenge of Taipei's Liang-Chi Huang 6-2 6-4 in one hour and 13 minutes. Yuki will next face Spaniard Gerard Granollers.
Indian qualifier Sanam Singh dumped French sixth seed and world number 169 David Guez 6-4 7-5 in one hour and 51 minutes to set up a pre-quarterfinal against compatriot N Sriram Balaji.
Wild card Balaji beat qualifier left-handed Prajnesh Gunenswaran 6-3 6-3.
It was an end of campaign for Balaji in doubles as he along with Blaz Rola from Slovakia lost 7-5 5-7 6-10 to the top-seeded Thai pair of Sanchai and Sonchat Ratiwatana.