Kolkata - South Africa rode on JP Duminy's robust 99 to storm into the Cricket World Cup quarter-finals with a crushing 131-run victory over Ireland on Tuesday.
The Proteas were wobbling at 117/5 after a tight bowling and fielding show by Ireland, but Duminy played a responsible knock to help his team post a challenging 272/7 in the day-night match at Eden Gardens.
The target proved too big for Ireland who were bowled out for 141 in 33.2 overs, with Gary Wilson top-scoring with 31.
South Africa currently top Group B with eight points from five matches, followed by India (7/5), the West Indies (6/4), Bangladesh (6/5) and England (5/5).
Ireland, with two points in five games, are eliminated.
"We wanted to qualify. We've got one round robin game left against Bangladesh and hopefully three good games in the knockout phase. We've done the first part of it now," said South Africa captain Graeme Smith.
Ireland captain William Porterfield said: "We started off pretty well. We got couple of wickets up front. We thought it was important to get wickets to peg them back and I thought we did that pretty much throughout."
"Chasing 270 was not out of our reach but we consistently lost wickets."
Ireland's chase under lights began on a shaky note when they lost openers Porterfield and Paul Stirling in the opening four overs, with Morne Morkel taking both the wickets.
Morkel ended the innings when he dismissed George Dockrell to finish with 3-33.
Wilson and Kevin O'Brien (19) offered brief resistance with a 41-run stand for the fifth wicket before both of them fell to left-arm spinner Robin Peterson in the space of three balls.
Peterson grabbed three wickets and seamer Jacques Kallis two.
Man-of-the-match Duminy earlier kept the Irish attack at bay with a commendable knock, adding 87 for the sixth wicket with Colin Ingram (46) and 65 for the next with Johan Botha (21 not out).
Morne van Wyk was the other notable run-getter with a brisk 42.
Duminy looked set to complete his third one-day hundred before he fell in the last over, brilliantly caught by Kevin O'Brien at mid-on off seamer John Mooney. He hit one six and six fours in his 103-ball knock.
Ingram, playing his first World Cup game in place of injured batsman AB de Villiers, hit seven fours in his 43-ball knock before being bowled by fast bowler Trent Johnston.
The non-Test playing nation did not allow South Africa to settle after they elected to field, with paceman Boyd Rankin and spinners George Dockrell and Paul Stirling taking one wicket apiece.
The Irish bowlers were backed by their fielders, with skipper Porterfield and Mooney having a hand in the run-outs of Kallis (19) and skipper Graeme Smith (seven).
The South African batting problems began in the fifth over when Hashim Amla (18) fell soon after pulling Rankin for a six, upper-cutting the next ball to Dockrell, who took a superb diving catch at deep third man.
Van Wyk went for his shots from the beginning as he twice lofted Johnston for fours and then hit two successive boundaries off Rankin.
He was lucky to survive on 23 when Stirling dropped a regulation slip catch off Rankin, but Ireland did not have to wait long for success as Smith was run out following a Mooney direct hit at the non-striker's end.
Van Wyk continued to play attacking shots as he smashed Johnston for two fours and a six in the same over before his flourish finally ended, bowled by left-arm spinner Dockrell while attempting to cut.