Already eliminated South Africa put a big dent in Sri Lanka's hopes of making the knockout stages of the Cricket World Cup as they won their clash on Friday in Durham by nine wickets.
An unbroken stand of 175 for the second wicket from captain Faf du Plessis (96 not out) and Hashim Amla (80 not out) saw the Proteas to their second victory of the tournament.
They sauntered to their winning total of 206-1 with 12.4 overs to spare after Sri Lanka had been bowled out for just 203 at Chester-le-Street.
Sri Lanka's innings had never got going with five players passing 20, but Kusal Perera and Avishka Fernando both top-scored on 30 as the batting line-up was pegged back.
Dwaine Pretorius (3-25) and Chris Morris (3-36) were the pick of the Proteas bowling as Sri Lanka were bowled out with three balls remaining of their 50 overs.
Despite losing Quinton de Kock (15) early, Amla and Du Plessis clinched an emphatic triumph.
Sri Lanka now must win both their remaining games against the West Indies on July 1 and India on July 6 to have any chance of reaching the knockout stages.
South Africa's final game is against the defending champions Australia on July 6, with the Australians already guaranteed a semi-final spot.
