Pakistan won by 21 runs to take a 2-1 lead in the five-match series after compiling 257 for eight and bowling out Sri Lanka for 236 in 48.5 overs.
The 34-year-old Jayawardene, batting at number five, made 17 as off-spinner SaeedAjmal and seamer UmarGul ran through the Sri Lanka card with three wickets apiece.
Earlier, Mohammad Hafeez (83) and ImranFarhat (70) put on 151 for the first wicket before Pakistan were pegged back by pacemanLasithMalinga (2-57) and leg-spinner SeekkugePrasanna (2-39).
Mohammad Hafeez and ImranFarhat hit half-centuries to anchor Pakistan to 257-8 off 50 overs against Sri Lanka in the third one-day international at Dubai International Stadium on Friday.
Hafeez smashed nine fours and a six in a top score of 83 off 101 balls while left-hander Farhat struck six fours and a six in 70 off 82 deliveries.
The pair set the platform with an opening stand of 151 in 29 overs.
But Sri Lanka hit back in the latter half of the innings through leg-spinner SeekkugePrasanna (2-39) and pace ace LasithMalinga (2-57).
Younis Khan's 42 off 52 balls rallied the hosts towards the end.
Hafeez and Farhat began steadily after Pakistan won the toss for the first time in the series and chose to bat.
The pair took 40 off the first 10 overs before raising the scoring rate to reach 100 off 20 overs.
Hafeez blasted four fours in one over from Dilhara Fernando and arrived at his half-century first, off 68 balls.
He benefited from three chances, at 7, 43 and 58.
ThisaraPerera first dropped a very hard return catch, then Malinga misjudged an upper cut at third man off Fernando. The third miss was at extra cover when Prasanna grassed a sharp drive off captain TillakaratneDilshan's offspin.
Farhat crossed his 50 off 60 balls and Pakistan was coasting at 150-0 after 29 overs.
But the innings subsided quickly when both openers perished within 10 runs.
Prasanna made the breakthrough when a flatter one rushed through to bowl Hafeez.
Dilshan removed Farhat, who holed out to long-on.
Pakistan slipped to 167-3 as Abdul Razzaq failed to deliver as a pinch-hitter, lofting Prasanna straight to long-on.
Malinga returned to further energize the Sri Lankans when he bowled UmarAkmal for 7.
Pakistan slid even further to 193-5 in the 40th over when captain Misbah-ul-Haq was comically run out after he and Younus Khan ended up in the same crease.
Younis and fellow veteran ShahidAfridi added a run-a-ball 33 for the sixth wicket to revive Pakistan.
Afridi made 15 off 15 balls before he skied Perera to long-on.
Malinga added the cheap scalp of Sarfraz Ahmed, bowled off the inside edge at 234-7.
Younis and SohailTanvireeked out a stand of 22 for the eighth wicket to take Pakistan past 250.
Younis, who hit three fours, was run out by Prasanna's direct hit from mid-wicket in the final over.
