Hashim Amla's wizardry then threatened to shut out the visitors before South Africa lost crucial wickets at the wrong times to make sure the rest of their chase wouldn't be as breezy as Amla's innings was. JP Duminy, though, kept his cool to guide his side home in the penultimate over.
AB de Villiers had earlier been lured into putting Sri Lanka in by overcast skies, but the visitors were able to survive and slowly build their innings, partly due to the lack of bite in the pitch and partly due to Chandimal and Tharanga. That South Africa got as much as 237 to chase was down largely to Chandimal. He batted till the end of Sri Lanka's innings, displaying grit - a quality that has been largely absent among Sri Lanka's batsmen recently.
Chandimal outside-edged heaves over point, he even lap-swept a ball off his helmet a four. Timing eluded him for most of his innings, but fortune did not. He repeatedly tried to smash the spinners out of the ground only for the ball to roll towards midwicket. He could have been run out several times as he went for tight singles. He had earlier been hit on the arm and the side of the helmet by Albie Morkel as he played a pull too early. But he just smiled and rode out the tough period. He hit his first four off the 16th delivery he faced, the next one came off the 85th as he carried Sri Lanka from 164 for 5 in the 40th over to 236 for 6 in the company of Angelo Mathews.
The visitors had initially found themselves in familiar territory at 21 for 2 after 10 overs despite the Buffalo Park pitch affording neither the pace nor the bounce that Paarl had. Tillakaratne Dilshan still managed to get dismissed off the fourth ball he faced for his second duck in as many games, a slight hesitation while attempting a tight single against the arm of Faf du Plessis finding him short of the crease. He now averages 15.50 with the bat in 18 ODIs since taking over the Sri Lanka captaincy.
Smart stats
Dinesh Chandimal's 92 is his fourth fifty-plus score in 19 matches. He has scored two centuries prior to this knock. His 92 is also the fifth-highest score by a Sri Lankan batsman against South Africa in ODIs in South Africa.
South Africa's win is their 14th against Sri Lanka in 20 home ODIs. Overall, they lead the head-to-head contests 24-22.
This is South Africa's 12th win in 18 matches in East London and their second win against Sri Lanka at the venue. Their last defeat at the venue came in 1994.
Hashim Amla's half-century is his 16th in ODIs and his second consecutive fifty-plus score against Sri Lanka. Since the beginning of 2011, his performance has dropped a little but he continues to average nearly 50 with three hundreds.
JP Duminy's half-century is his 15th in ODIs overall and first against Sri Lanka. He has made 11 of his 17 fifty-plus scores in home ODIs.
This is South Africa's tenth successful chase in ODIs against Sri Lanka. The target of 237 is the second-highest that South Africa have managed to chase down in matches against Sri Lanka. The highest is 248 in Paarl in 2001, when South Africa went on to win by eight wickets.
With edges dying on the wicketkeeper and batsmen being beaten after playing their shots too early, it was no surprise that Lonwabo Tsotsobe's assortment of slower deliveries and cutters proved difficult to score off. After having played the patience game in making 3 off 27 deliveries, Kumar Sangakkara fiddled with a Tsotsobe delivery outside off stump and feathered a dying edge to the wicketkeeper.
Tharanga and Chandimal were tested more by the slowness of the pitch than by South Africa's bowlers. But to their credit, they were prepared to wait and nudge the ball around. Tharanga, the only Sri Lanka batsman to find some measure of timing on the pitch, glided deliveries for boundaries through point, and when the spinners found some help from the pitch he stepped out to loft them down the ground. An attempt to glide Morne Morkel towards third man resulted in a faint edge to the keeper after he had motored to 66.
South Africa's excellence in the field earned them the wickets of Mahela Jayawardene and the promoted Nuwan Kulasekara, both after breezy cameos. Chandimal ultimately carried them to a score that was seven runs short of the average total by a side batting first at Buffalo Park.
Sri Lanka needed Lasith Malinga to strike early if they were to make the target of 237 seem bigger than it was, but Amla and Graeme Smith were careful to play out his opening burst with caution. With Malinga out of the way for the moment, Amla began to toy with the rest of the attack, untroubled by the slowness of the track. He smashed Nuwan Kulasekara for six over extra cover, walked across to flick him for four through midwicket and flicked him over square leg for six.
Dilshan soon did what he so often does when there are no answers to be found: he brought himself on. Amla guided and nudged him for consecutive fours to race towards his half-century. Dhammika Prasad gave Sri Lanka much-needed relief as Amla finally failed to connect and was bowled for 55.
Rangana Herath, who had been held back, came on and troubled Kallis immediately with sharp turn as well as with arm balls. A slow partnership between Kallis and Duminy followed, which served to push the asking-rate up. With 85 needed from 15 overs, Kallis sliced Prasad straight to sweeper cover in an attempt to speed up the scoring.
de Villiers came in charged up and soon ran himself out, attempting a non-existent single to short third man. But Amla's start had afforded South Africa the space to wobble a bit. Duminy did what was required, working the singles and pushing for the twos. He hit only one boundary off 87 deliveries but still scored at a strike-rate of over 75. It wasn't fancy stuff, it wasn't the artistry of Amla, but South Africa would be grateful to Duminy for doing the dirty work that steered home what should have been a far smoother chase.
