Both Seekkuge Prasana  and wicket-keeper Kumar Sangakkara [44 not out] scored at better than a strike rate of 200, as Perera, who top scored with 84 from 59 balls, continued to anchor the innings.
When he was ran out on the final ball, Sri Lanka had amassed 211 and four of the six bowlers used by Pakistan had gone at over 10 runs an over, with Ajmal and Tanvir the pair that avoided a bludgeoning.
They were left with it all to do with the bat, too, after the Men in Green collapsed to 85-7, with only Sharjeel Khan  contributing out of the top eight, three of which were dismissed for ducks.
Tanvir went on the attack and surprised Sri Lanka with an explosive knock of 41 from 26 balls, while Ajmal also smashed a quickfire 20 to take Pakistan to within 30 with two overs remaining.
However, death-bowling specialist Lasith Malinga kept things tight and had Tanvir caught to effectively end the contest in the 19th over, with Nuwan Kulasekara claiming the final wicket to dismiss Pakistan for 187.