Hasan heroics and Malik might leave Sri Lanka stumped yet again
Pakistan celebrated an eight ODI win on the spin, but Sri Lanka are now nursing a run of 11 defeats on the bounce in the format.
Shoaib Malik and Babar Azam made short work of Pakistan's chase after Hasan Ali celebrated becoming the world's top-ranked ODI bowler by ripping through Sri Lanka.
Hasan has gone from strength to strength since playing a key role in Pakistan's stunning Champions Trophy win and he took 3-37 to set the nominal hosts in Sharjah on their way to an eighth straight 50-over win.
Sri Lanka are also on a sequence of results in this format, although one much more painful, and they never looked like preventing a losing run slipping to an 11th match after being bowled out for 173.
After Hasan's heroics, Babar and Malik each scored 69 not out, putting an unbeaten 119 runs on for the fourth wicket and sealing victory and putting Pakistan in sight of a series whitewash in the fifth and final contest, with Sri Lanka hoping to avoid successive blowouts in ODIs.
Sri Lanka's innings was sapped of momentum from the off, with Upul Tharanga (0) and Niroshan Dickwella (22) falling in the powerplay.
Lahiru Thirimanne scored 62 but his resistance was the only real nuisance for Pakistan, who twice took two wickets in an over - Dinesh Chandimal (16) and Sadeera Samarawickrama (0) falling in the 11th, while Shadab Khan (2-29) enjoyed immediate success, snaring Seekkuge Prasanna (5) and Thisara Perera first ball with his opening two deliveries of the match.
Sri Lanka were 99-7 at that point, with only useful cameos from Akila Dananjaya (18) and Suranga Lakmal (23 not out) alongside Thirimanne helping them to something resembling a decent target.
It proved wholly insufficient, however, Pakistan riding out the cheap dismissals of Imam-ul-Haq (2), Mohammad Hafeez (9) and Fakhar Zaman (17).
Babar and Malik took their time to get going and the latter had a life on three when a chip to mid-on burst the hands of Thisara.
Malik was back in the groove by the time he launched Dananjaya 93 metres over midwicket and Sri Lanka's limp performance soon extended to their bowling and fielding as Pakistan were allowed to calmly chip away at their target.
With victory in sight, Malik delighted the crowd with a sumptuous blast over extra cover for another maximum, and his third six finished the match as Pakistan sealed the win with 11 overs unused.