Hashim Amla's 112 propelled the Proteas to their big score. (AP)
Paarl: Sri Lanka crashed to 43 all out on Wednesday to equal the fourth lowest total ever in a one-day international, losing by a huge 258-run margin to South Africa.
Sri Lanka slumped to their worst score in ODIs and were in danger of setting a new world record low at 33-8 before the ninth-wicket pair of Kosala Kulasekara and Nuwan Kulasekara dragged the tourists past the 35 Zimbabwe scored against the Sri Lankans in 2004.
Sri Lanka were the bowling team in all of the three lowest totals in ODIs but their batsmen were on the receiving end at Boland Park as South Africa pace bowlers Morne Morkel and Lonwabo Tsotsobe ripped through the top order with deadly swing and bounce.
South Africa won by the third biggest victory margin by runs ever in ODIs after they made 301-8 batting first. It gave AB de Villiers a dream start to his career as South Africa's new one-day captain.
Hashim Amla's 112 propelled the Proteas to their big score, helped by rapid half-centuries from Jacques Kallis and new limited-overs skipper De Villiers.
Morne Morkel then took 4-10 and left-armer Tsotsobe 3-19 as Sri Lanka slumped to 13-6 and were all out in 20.1 overs. Left-arm spinner Robin Peterson picked up 2-5 in 3.1 overs.
"Obviously the dream start for me," De Villiers said. "It was a really quality team performance. Some individuals stand out ... but a team performance is what comes to mind."
Sri Lanka fast bowler Lasith Malinga's 5-53 went to waste as the batsmen crumbled to their worst score, with Kosala Kulasekara (19) the only one to make double figures. Just three boundaries were hit in the innings and Sri Lanka lost their first five batsmen in five overs. Only minnows Canada and Zimbabwe have made lower totals.
"A really bad performance," Sri Lanka captain Tillakaratne Dilshan said. "We are a much better team than we showed today. We just have to look forward to starting the second ODI strongly. It was very difficult to come back (from the early wickets)."
Sri Lanka lost Upul Tharanga off the second ball of the innings and opening partner Dilshan off the eighth - both for ducks - in a terrible start.
Wickets tumbled rapidly with Dinesh Chandimal out in the fourth over. Kumar Sangakkara and Angelo Mathews fell within three balls in the fifth, and Mahela Jayawardene flashed a cut shot straight to Faf du Plessis at point in the eighth for 13-6.
Kosala Kulasekara top-scored in just his second ODI as Sri Lanka scraped past 35.
But Peterson bowled Malinga for a duck and had last man Dilhara Fernando lbw, also for 0, to wrap up a one-sided win. In between, Morkel returned for his second spell to dismiss Kosala Kulasekara with his fifth ball back.
"I'm very happy just to be able to perform well for the team tonight," the lanky fast bowler said.
Earlier, Amla shared a 144-run partnership with Kallis (72) and a 91-run stand with De Villiers (52) after Malinga struck in the third over to remove Graeme Smith.
Amla hit eight fours for 112 off 128 deliveries - his ninth ODI hundred - and De Villiers made his rapid half-century off just 40 balls.
Malinga returned with a typically devastating spell near the end to remove Amla, Albie Morkel (25), Du Plessis and Dale Steyn to slow South Africa's scoring.
The right-arm quick dismissed Du Plessis and Steyn in the final over for his fifth five-wicket ODI haul as South Africa faded from 244-3 when a score of 350 - and an even bigger win - was in the host's sights.
South Africa slipped up to lose five wickets for 22 runs in less than five overs at the end but Sri Lanka's dramatic collapse gave the Proteas their second biggest win - and one-day cricket's third largest - behind a 272-run victory over Zimbabwe two years ago.