Top seed J Vishnu Vardhan had to dig deep into his reserves to overcome a spirited challenge from a rival placed 500 places below him to enter the second round in the USD 15,000 CCI-ITF men’s Futures tournament on Tuesday. Davis Cupper Vishnu, who took part in singles as well as doubles at London Games, fought hard to chalk out a 6-4, 5-7, 6-3 victory in two hours and 16 minutes over Secunderabad city rival Ashwin Vijayraghavan. The 25-year-old six-footer, ranked 272nd in the world, was on course for a straight-set win when he served for the match at 5-3 in the second set before his 20-year-old rival clawed his way back. But Ashwin lost steam in the sweltering heat after clinching the second set.