The 32-year-old right-arm paceman took 4-30 in a superb display of swing bowling to detrack the Sri Lankan innings in which Dinesh Chandimal topscored with 56 after Sri Lanka won the toss and decided to bat on a slow pitch.
Dilshan miscued a drive off spinner Saeed Ajmal in the sixth over but Sri Lanka still had a ten run avergae by the sixth over. Pakistani bowlers led by Cheema, playing only his second Tewnty20 match, checked Sri Lankan innings as they lost their last seven wickets for 54 runs.
Chandimal brought up his maiden half-century in the shortest form of the game off 40 balls before Cheema had him in the 19th over of the innings, trapped leg-before. Cheema also had Thissara Perera (nought) and Lasith Malinga (one) to finish his four-over spell.
Sri Lanka's poor batting was not helped by two run outs of Angelo Mathews (14) and Chamara Silva (four).