England have assured themselves of a place in the semi-finals of the World Twenty20 in India with a 10-run victory over Sri Lanka, knocking out the defending champions in the process.

Jos Buttler starred with the bat as England set Sri Lanka 172 to win, a target that they fell 10 short of, despite a game-high knock of 72 from captain Angelo Mathews.

England were put into bat by Mathews after Eoin Morgan lost the toss and Alex Hales was gone for a four-ball duck in the second over, trapped lbw by Rangana Herath.

That brought the Super 10s top scorer Joe Root (25) to the crease, and he put on a second-wicket stand of 61 with Jason Roy before slapping Jeffrey Vandersey straight to Lahiru Thirimanne on the boundary.

Roy was next to go for 42 as Vandersey got him lbw, but that left Buttler and Morgan at the crease to push England's innings on with a 74 partnership.

Morgan fell in the final over for 22, but it was Buttler writing all the headlines at the other end as he finished unbeaten on 66 off 37 balls. Ben Stokes faced one ball right at the end of the innings and whacked it away for six as England reached 171-4.

Sri Lanka's reply started slowly as the 2014 champions lost four wickets in the first three overs.

David Willey removed Tillakaratne Dilshan (2) and Milinda Siriwardana (7), while Chris Jordan took out Dinesh Chandimal (1) and Stokes acrobatically ran out Thirimanne.

Mathews and Chamara Kapugedera steadied the ship with a fifth-wicket stand of 80 that gave Sri Lanka hope of snatching an unlikely win.

Liam Plunkett finally broke the partnership with the wicket of Kapugedera (30), but Thisara Perera came in and scored quickly before he fell for 20 off Jordan.

Jordan finished with four wickets and his third was the pick of the lot as Root dived high to his left to remove Dasun Shanaka (15).

Mathews finished unbeaten on 73 but could not score enough runs in the final over as Stokes frustrated him with a succession of yorkers.

With victory, England join West Indies in qualifying from Super 10 Group 1 and they are likely to face unbeaten New Zealand in the last four. Sri Lanka and South Africa both exit at the group stage.