With the win, South Africa reached their third final in the sub-continent. They will now have to wait for the outcome of today's second semi-final to know their November 1 final opponents.
Jacques 'sensational' Kallis hammered the third century of the tournament, a career-best unbeaten 113 off 110 balls, as South Africa, sent into bat by Sri Lankan skipper Arjuna Ranatunga, amassed a commanding 240 for seven in 39 overs.
In reply, Sri Lanka, given a revised target of 224 runs in 34 overs for victory, were all out for 132 in the 23rd over. Number eleven Muralitharan, who had a shoulder injury while fielding, did not turn up to bat.
The outcome of yesterday's match meant an early exit of another sub-continental giant from the knock-out tournament after Pakistan were dumped by West Indies on Thursday. Only India remain in the race.
The islanders were never up in their chase against the soaring run-rate, which was 6.58 at the onset. Explosive opener Jayasuriya scored a breezy 22 off 17 balls, Chaminda Vaas, promoted up in the batting order, and Aravinda de Silva scored 18 runs each.
Atapattu scored a characteristic 19. But there was none to build the innings in the face of some controlled South African bowling backed by flawless, at times sensational, fielding, specially from master fieldsman Jonty Rhodes.
Right-arm seamer Elworthy, playing only his sixth one-day international, drew the first blood. Bowling a teasing line, he claimed three of the Sri Lankan top order -- Kaluwitharana, Jayasuriya and batting maestro batsman Aravinda de Silva -- in his three successive overs. Elworthy finished with three for 21 in his four overs. He was ably supported by off-spinner Symcox, who took three wickets for 27.
The day-night match got off to a delayed start due to over-night rain and light drizzle in the morning. The rain damaged the outfield, specially the bowler's run-up at the VIP end.
A massive work by the dedicated groundsmen and volunteers finally made possible at least a truncated match, much to the delight of the full-house crowd at the big bowl. Some of the 'early bird' fans had braved the rain and waited for more than nine hours, which drew showers of praise from WorldTel commentators.
Earlier, South Africa's impressive total was built around brilliant Kallis knock coming in defiance of the inclement weather. He hammered his third one-day century playing only 91 balls, the quickest of the tournament so far.
Coming into bat at number five with South Africa reeling at 3/57, the stockily-built right-hander set the stadium alight with a flurry of shots all around. Kallis, who was particularly harsh on off-spinner Muralitharan, smote five sixes, so far the highest in an individual innings in the tournament, and as many fours in his flawless innings.
The Middlesex all-rounder held the South African innings together after Cullinan departed after a 43-ball 30. He shared 81 runs for the fifth wicket with skipper Hansie Cronje, who scored a workmanlike 20. Despite wickets falling at the other end at regular intervals, Kallis was generally well-supported by the lower middle-order to throttle the Proteas to a commanding total.
Among the Sri Lankan bowlers, leg-spinner Upul Chandana and left-arm seamer Nuwan Zoysa took two wickets each. Muralitharan returned most expensive with figures of one for 48 in his six overs.
Kallis was the obvious choice for the man-of-the-match award.
South Africa may have won the rain-ruled match, but the real voctors were the two sporting captains who agreed to continue play and the marvellous crowd that kept waiting.