A stoic 56-ball 83 from Tillakaratne Dilshan helped Sri Lanka record their first win of their T20 World Cup campaign by beating a gritty Afghanistan by six wickets at the Eden Gardens on Thursday.

Afghanistan, who impressed in the qualifiers by beating Scotland, Hong Kong and Zimbabwe, hoped to carry on their winning ways by undoing a relatively inexperienced Sri Lanka outfit. After Captain, Asghar Stanikzai, opted to bat - at the toss - Afghanistan lost in form opener, Mohammad Shahzad, for just eight in the third over.

Stanikzai and Noor Ali Zadran then dropped anchor and began rebuilding the innings. The duo scored at a rate of six and over, and added 32 runs, before Zadran fell for 20 in the ninth over. Two-more Afghan wickets fell in a span of two over thereafter, which brought Stanikzai and Samiullah Shenwari together.

The duo switched gears in the 13th over, when Stanikzai launched Milinda Siriwardana's left-arm spin, for successive sixes, before slog-sweeping, Rangana Herath, for another six in the 15th over. At the other end, Shenwari hit two fours and a six in successive overs. The onslaught helped Afghanistan, who managed 106 runs in the last ten overs, recover to post a respectable 153.

Sri Lanka's captain, Angelo Mathews, at the toss had said that he wanted a 'clinical' display from his side in their opener. Dilshan, who eventually led the successful chase, ensured that his side started on a positive note.

Dilshan and his opening-partner Dinesh Chandimal gave the team a solid start and added 41 in the first five overs. Lahiru Thirimanne, back in Sri Lanka's T20 side for the first time since May 2014, departed three-overs later. Dilshan provided the stability required to power the chase. He set the tone with consecutive sixes off Dawlat Zadran in the third over. The second six came off a trademark scoop over his-own head.

In the next over, Dilshan swatted Hamid Hassan for successive fours over midwicket. He was cautious against the spinners and took the singles on offer. In all, Dilshan hit eight fours and three sixes. Afghanistan added to their own woes by a poor fielding display. Dilshan and Mathews combined for a 42-run stand for the fifth wicket to guide Sri Lanka home in the 19th over.

"Two games I had two ducks, but I needed runs going into the big games. I'm really happy that I finished the game," Dilshan said. "150 is a good total, this wicket is slow. Later a little dew helped. They had some quality bowlers but we managed very well in the middle. Twos and threes, every wicket we tried to put up a small partnership. Come to these kinds of tournaments, first match is very important that I get some runs. Senior guys need to stand up and do it for the team. The middle order can bat around us."