Lonwabo Tsotsobe grabbed 3-14 on his World Cup debut as mighty South Africa sent Bangladesh crashing out of the tournament with a 206-run victory on Saturday.
Jacques Kallis made 69 and Faf du Plessis hit a run-a-ball 52 to lift South Africa to 284-8 after Graeme Smith won the toss and elected to take first strike on a slow, sluggish wicket.
Bangladesh, needing a win to qualify for the quarter-finals, were shot out for 78 in reply after Tsotsobe ripped through the top order and left-arm spinner Robin Peterson claimed 4-12 at the end.
Skipper Shakib Al Hasan made 30 but none of the other 10 batsmen reached double figures as Bangladesh almost matched their lowest one-day total of 58 against the West Indies earlier in the tournament.
The emphatic win not only cemented South Africa's place as Group B winners with 10 points, but also carried India and England into the quarter-finals with the West Indies set to take the last spot.
Bangladesh ended the league with six points, the same as the West Indies, but their run-rate is so poor that even a massive win by India over Darren Sammy's men on Sunday will not help.
Tsotsobe, who was given a chance only because pace spearheads Dale Steyn and Morne Morkel were rested ahead of the bigger matches, seized the opportunity in style.
The 27-year-old left-arm seamer silenced a sell-out crowd of 25,000 home fans at the Sher-e-Bangla stadium when he had Bangladesh's main batting hope, Tamim Iqbal, caught behind for five in his second over.
Tsotsobe bowled Imrul Kayes and Shahriar Nafees and off-spinner Johan Botha trapped Junaid Siddique leg-before to dash Bangladesh's hopes.
Mushfiqur Rahim was caught in the slips off Peterson and Mohammad Mahmudullah was run out as Bangladesh slipped to 58-6 by the 22nd over.
Peterson had Shakib caught behind and then removed Shafiul Islam and Abdur Razzak in one over and bowled Naeem Islam to end the innings.
Earlier, Kallis mastered the slow wicket to hit five boundaries and a six in his ninth World Cup half-century, sharing a fourth wicket stand of 82 with Faf du Plessis.
They laid the platform for a late assault which saw the lower order batsmen smash 92 runs in the last 10 overs.
South Africa made a solid start as Smith and Hashim Amla (51) put on 98 for the first wicket by the 21st over.
Smith, on 26, survived a close call for leg-before when he asked for a review after being given out by umpire Daryl Harper.
Replays indicated an on-field call -- which usually means the batsman has to go -- but Harper overturned his own decision to the surprise of bowler Razzak.
Smith equalled his best score of 45 in this World Cup, against the West Indies in the first match, before he was stumped off Mahmudullah attempting a big hit.
Amla fell two overs later when he played a delivery from Razzak onto his stumps to make South Africa 107-2.
When JP Duminy was caught down the leg-side by the wicket-keeper while trying to hook Rubel Hossain, South Africa were 141-3.