The 33-year-old left-hander, returning after dislocating his shoulder three weeks ago, smashed an unbeaten 102 as the hosts coasted to 201 for two with more than 13 overs to spare in reply to Pakistan’s 200 all out.
With minnows Holland the other team in pool four, Sri Lanka are now virtually assured of a place in the semifinals, while Pakistan face almost certain elimination from the 12-team competition.
Jayasuriya had been doubtful for the game after dislocating his right shoulder while leading his side to victory in a one-day tournament in Morocco on Aug 21.
After edging fast bowler Wasim Akram over second slip for four to get off the mark he played some punishing shots during his 119-ball knock which included 10 fours.
He cut off-spinner Shoaib Malik to the cover fence to bring up his century before raising his bat to the cheering crowd and walking over to embrace partner Aravinda de Silva, who finished unbeaten on 66, his 60th One-day International half-century.
Pakistan briefly reduced Sri Lanka to 45 for two after Marvan Atapattu was run out and Kumar Sangakkara bowled by Wasim Akram before the experienced Jayasuriya and de Silva took over in an unbroken third-wicket partnership of 156.
Pakistan were dealt a blow before the game when key batsman Inzamam-ul-Haq was ruled out with a heel injury and nothing went right for them when the game began after winning the toss.
The Sri Lankan seamers reduced Pakistan to 17 for three and only patient efforts by opener Saeed Anwar (52) and Misbah-ul-Haq (47), who just missed his third 50 in only his fifth game, took them to the respectability of 200.
Shoaib, one of the three early victims, made history when he became the first batsman given out lbw by the third umpire after being trapped in front of his stumps by Chaminda Vaas.
Umpire Daryl Harper referred the decision to television umpire Rudi Koertzen who decided the ball had pitched in line with the wicket.
Under experimental regulations in force for the tournament, field umpires can refer any decision, including lbws and bat-pad catches, to the third umpire.
Saeed Anwar scored his 43rd one-day fifty and shared a 70-run fourth wicket partnership with Younis Khan (35).
But off-spinner Muttiah Muralitharan once again led the bowling, taking three for 29 from his 10 overs while fast bowler Dilhara Fernando finished with three for 30 after taking two wickets in his final over.
PAKISTAN:
Saeed Anwar c Chandana b F’nando 52
Shahid Afridi c S’kkara b G’ratne 4
Shoaib Malik lbw b Vaas 1
Yousuf Youhana run out 0
Younis Khan b M’tharan 35
Rashid Latif c F’nando b M’tharan 22
Misbah-ul-Haq b F’nando 47
Abdul Razzaq c de Silva b G’ratne 16
Wasim Akram b M’tharan 0
Waqar Younis c de Silva b F’nando 4
Shoaib Akhtar not out 0
EXTRAS (LB-8, W-3, NB-3, PEN-5) 19
TOTAL (all out, 49.4 overs) 200
FALL OF WKTS: 1-12, 2-17, 3-17, 4-87, 5-120, 6-141, 7-171, 8-175, 9-198.
BOWLING: Vaas 10-3-27-1; Gunaratne 10-1-49-2; Fernando 9.4-0-30-3 (3nb, 3w); Chandana 7-0-37-0; Muralitharan 10-0-29-3; Jayasuriya 3-0-15-0.
SRI LANKA:
S.T. Jayasuriya not out 102
M.S. Atapattu run out 8
K.C. Sangakkara lbw b Wasim 0
P.A. de Silva not out 66
EXTRAS (B-2, LB-7, W-10, NB-6) 25
TOTAL (for two wkts, 36.1 overs) 201
FALL OF WKTS: 1-44, 2-45.
DID NOT BAT: D.P.M. Jayawardena, R.P. Arnold, U.D.U. Chandana, W.P.U.J.C. Vaas, C.R.D. Fernando, M. Muralitharan, P.W. Gunaratne.
BOWLING: Wasim Akram 8-0-42-1 (4nb, 1w); Waqar Younis 5-0-37-0 (2w); Shoaib Akhtar 8-0-36-0 (2nb, 2w); Shahid Afridi 7.1-0-39-0 (1w); Abdul Razzaq 3-0-14-0 (1w); Shoaib Malik 5-0-24-0 (3w).
RESULT: Sri Lanka won by eight wickets.
UMPIRES: S.A. Bucknor (West Indies) and D.J. Harper (Australia).
TV UMPIRE: R.E. Koertzen (South Africa).
MATCH REFEREE: M.J. Procter (South Africa).
MAN-OF-THE-MATCH: Sanath Jayasuriya.
NEXT MATCH: West Indies v South Africa, SSC Ground, Friday.—Reuters