Pakistan succumbed to their lowest one-day score in five years as a pathetic 102 all out helped Sri Lanka claim a seven-wicket victory in the series decider in Dambulla.
The tourists were badly let down by their batsmen as they were dismissed for their worst total in Sri Lanka when lasting just 32.1 overs, with just three batsmen reaching double figures and only Fawad Alam showing any sort of resolve in his 38 not out.
Thisara Perera took four lower-order wickets but Pakistan's batsmen only had themselves to blame for their calamity before Sri Lanka comfortably knocked off the runs with a whopping 178 balls to spare, thanks to Tillakaratne Dilshan's unbeaten 50, as they clinched the series 2-1.
Their task was made ever so slightly easier as heavy rain meant the contest was reduced to 48 overs per side and Sri Lanka's victory target narrowed down to 101.
Dilshan settled into his stride with three crunching fours in the second over as Sri Lanka's opening stand put on 46 to all but ensure the win.
Upul Thranga, Kumar Sangakkara and Mahela Jayawardene were all dismissed but Dilshan led the way, taking Sri Lanka past their victory target in the 19th over with his ninth four that also brought up his half-century.
But Sri Lanka were earlier grateful for the type of implosion only usually reserved for Pakistan, who chose to bat after winning the toss.
Dhammika Prasad removed openers Sharjeel Khan and Ahmed Shehzad, and Pakistan had lost their top three batsmen before the eighth over when Lasith Malinga had Mohammad Hafeez trapped in front by an inswinger that would have gone on to clip leg stump.
Pakistan's efforts were further undermined when captain Misbah-ul-Haq found himself well short of his ground after attempting a quick single - with Angelo Mathews' throw from point condemning his opposite number to the third run-out in his last seven innings.
Umar Akmal's needless slash to mid-on gave Perera the first of his four scalps, while Shahid Afridi fell in characteristic fashion, caught on the off-side aiming a big heave off Seekkuge Prasanna.
An hour's rain delay meant Sri Lanka had to wait to polish off their opponents but there was to be no wag in the tail from Pakistan, with Fawad left stranded following a resolute 73-ball innings that contained three fours.
It was Pakistan's lowest total in an ODI since they crumpled to 75 all out against the same opposition in Lahore in 2009 and ultimately handed victory to Sri Lanka.