IRELAND suffered their first defeat of the World Cup after losing to South Africa by 201 runs in Canberra.
Hashim Amla hit his highest one day score of 159 whilst Faf du Plessis reached 109 in South Africa's 411-4, before Ireland were dismissed for 210 at the Manuka Oval.
Ireland came into the match with two wins from two, but were not able to recover from 48-5 as they were bowled out in 45 overs.
Andrew Balbirnie top-scored for Ireland with 58, but this was not enough to challenge South Africa, who have now passed 400 in two successive Pool B games.
South African captain AB de Villiers managed only 24 off nine deliveries, but Amla and Du Plessis struck 247, before Rossouw and David Miller hit 110 off the last 8.3 overs.
Amla should have been caught on 10 by Ed Joyce, and similarly, Du Plessis, on 19, after edging between wicketkeeper Gary Wilson and Kevin O'Brien slip.
Instead he reached his 20th one-day century in a partnership of 247 with Du Plessis, a record second-wicket stand for South Africa.
Du Plessis reached 109 from as many balls for his fourth one-day-international century, with Rilee Rossouw impressing with 61.
An Ireland victory became unimaginable as Dale Steyn and Abbott picked up five wickets in the first 11 overs.
Balbirnie and O'Brien's sixth-wicket stand of 81 helped Ireland avoid a heavy defeat, but the focus was primarily on damage limitation to their net run rate.
Kyle Abbott finished with 4-21 and fellow pace bowler Morne Morkel 3-34.
Ireland still have a strong chance of qualifying through to the quarter-finals, although their net run rate will have been affected ahead of Saturday's game against Zimbabwe in Hobart.
South Africa will qualify if they win one of their remaining two group games, against Pakistan and the UAE.