Perhaps it is because Pakistan had not played Hasaranga since 2019 (he has been a much-improved bowler since then), that they appeared especially powerless against his primary weapon - the ball that turns into the right-hander. He conceded just six runs in his first two overs. When Babar Azam, who had moved to 30 off 28, finally came down the track and took a chance, he was beaten comprehensively - Hasaranga slipping a straighter one beneath his bat, and onto the wickets.
That spell had been set up by Sri Lanka's tight bowling in the powerplay. On a worn track, Sri Lanka conceded only a single boundary off the bat in the first five overs - seamers Pramod Madushan (on debut) and Dilshan Madushanka, largely keeping things tight, while fingerspinners Maheesh Theekshana and Dhananjaya de Silva also contributed decent overs. The sixth over went for 12 runs, but thanks in part to Hasaranga, Sri Lanka kept a tight lid on the scoring.
Pakistan's bowlers had an even better powerplay than Sri Lanka's, thanks largely to Mohammad Hasnain and Haris Rauf who picked up three early wickets, and provided hope. Hasnain got one to bounce on Kusal Mendis second ball, the batter edging that to slip. Extra bounce also helped Rauf take Danushka Gunathilaka's outside edge next over, with Mohammad Rizwan diving acrobatically to his right to pouch the chance.
That was as good as it got for Pakistan, though. Rajapaksa hit a couple of sixes off Usman Qadir early in the middle overs to get Sri Lanka well ahead of the required rate. Nissanka accumulated safely at the other end. They hit occasional boundaries, and though Rajapaksa got out with 42 still to get, they had 51 balls to get them in.
Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. @afidelf