India's Devdutt Padikkal struck his maiden test hundred to underline his credentials for the number three slot and propelled the tourists to a commanding 288-2 in the first test against Sri Lanka in Galle on Saturday.India had been fretting over the one-down position after Sai Sudharsan, one of the seven batters tried in that position in the last two years, ‌was ruled out ⁠with ⁠a toe injury.It opened the door for Padikkal, and the left-hander responded with a free-scoring 131 not out, putting India on course for a formidable first-innings total on the opening day of the test at the Galle International Stadium.Opener KL Rahul made a composed 77 before retiring hurt.India got off to a fluent start after captain Shubman Gill opted to ​bat first on a track that promised plenty of ⁠runs.Yashasvi Jaiswal ‌and Rahul added 47 for the opening wicket before an almighty ​mix-up left ​both batters stranded at the non-striker's end.Jaiswal (32) was run out, ⁠but Rahul joined forces with Padikkal in a 150-run stand ​that kept Sri Lanka wicketless through the rain-delayed second session.Padikkal ​nearly offered a return catch to Sri Lanka captain Dhananjaya de Silva early in his innings but was otherwise the epitome of elegance.Having opened his account with a boundary, the southpaw stepped out against Prabath Jayasuriya and lofted the left-arm spinner over his head for six.Padikkal's aggression appeared to rub off on Rahul, who ‌gave Jayasuriya similar treatment in the spinner's next over.Padikkal brought up his half-century with a single off Lahiru Kumara, while Rahul soon reached ​his own ​fifty as the pair ⁠milked the Sri Lanka attack with consummate ease.As the runs continued to flow, Rahul developed cramps and retired hurt after an assured knock featuring nine fours and a ​six.Gill, who made 16, struck two sweetly timed boundaries before throwing away his wicket. The right-hander charged at Jayasuriya, only to sky a catch to mid-off.Rishabh Pant made a breezy unbeaten 27 and will look to continue his fine start when play resumes in India's 600th test, and also the 50th test at Galle.