Eighth seed Borna Coric was pushed all the way by Spain's Marcel Granollers but eventually prevailed on the opening day of the Chennai Open.
Croatian Coric, currently working under the guidance of Andy Murray's former coach Miles Maclagan, ground out a 7-6 (7/5) 2-6 6-4 first-round win over 2014 semi-finalist Granollers.
There was another clash between a Croatian and a Spaniard on Monday and once again it was the eastern European that emerged victorious, with qualifier Ante Pavic edging Nicolas Almagro 3-6 7-5 7-6 (7/1).
In the day's other game, Australia's John Millman saw off Russian Evgeny Donskoy 6-7 (5/7) 6-4 7-6 (8/6).
Tuesday's action includes seventh seed Vasek Pospisil taking on British number two Aljaz Bedene, who was a surprise runner-up in 2015.
Last year's winner and top seed Stan Wawrinka has a bye into the second round.
Source: PA
