Shaheens then made further inroads in the Sri Lankan innings as Ahmed Daniyal removed their skipper Dunith Wellalage in the ninth over, while Sufyan removed Ramesh Mendis in the subsequent over.
Saad then landed his second blow in 12th over and third in 14th over to leave them 99-8, with the asking rate nearing nine as Rathnayake took centre stage.
For Shaheens, Sufyan and Saad’s bowling analysis read as 3-12 and 3-18, respectively, while Daniyal, Shahid and Ubaid picked up one wicket each.
Earlier, Pakistan Shaheens slipped to 62-5 after Sri Lanka has opted to bowl first. Opening batters Maaz Sadaqat (23, 11b, 2x4s, 2x6s) and Mohammad Naeem (16, 15b, 3x4s) put on 30-run stand in 3.4 overs before Sri Lanka bowlers got into the act.
Shaheens lost four wickets for 22 runs after being 40-1 in 4.3 overs, which brought top-scorer Muhammad Ghazi Ghori (39 not out, 36b, 2x4s, 1x6) and Saad Masood (22, 25b, 3x4s) to the middle. The duo put on 47 runs for the sixth wicket to push Pakistan past the three-digit mark.
Ahmed Daniyal (22, 8b) provided Shaheens the late flourish with three sixes, two of which came in the 19th over, while one in the last over as they posted a competitive 153-9 in the allotted 20 overs.
For Sri Lanka, Pramod Madushan picked up 4-29 in four overs, while Traveen Mathew returned figures of 4-0-22-3.