Dhaka: South Africa rode on an unbeaten half-century by Graeme Smith to thrash Bangladesh by seven wickets and become the top-ranked one-day side in the world here on Friday.
Smith hit three fours and three sixes in his 94-ball 68 as the visitors overhauled the target of 143 with nearly 16 overs to spare for a 3-0 whitewash. South Africa, who were level with Australia on points at the top of the one-day rankings before the series, completed the feat with a clinical display.
Smith, 27, also surpassed 5,000 runs in one-dayers after reaching the same mark during the South Africans' 2-0 win in the preceding two-Test series.
The Proteas' captain, who reached his 36th half-century with a four off left-arm spinner Abdur Razzak, brought off the winning runs with a huge six over long on.
Bangladesh, on the other hand, slumped to their 14th one-day international defeat in a row, with their last win coming against South Africa in a World Cup super eight match last year.
South Africa were off to a cautious run chase, scoring their first 50 off 101 balls before Smith joined A.B. de Villiers (40) to put on a 79-run stand for the third wicket and steer the team to victory.
Earlier man-of-the-match Albie Morkel picked a career-best 4-29 while off-spinner Johan Botha chipped in with 3-34 as the hosts were bowled out in 42.5 overs on a placid wicket at the Sher-e-Bangla stadium.
None of the Bangladeshi batsmen showed the patience or temperament to stand up to a second-string South African bowling attack, throwing away their wickets recklessly.
Half the Bangladesh side were back in the pavilion for just 97 after skipper Mohammad Ashraful won the toss and elected to bat for the third time in a row.
Tamim Iqbal (eight) was unlucky to be adjudged caught behind off Morkel as TV replays showed the ball clipping the pad and not the bat.
But there was no such doubt when Iqbal's opening partner Shahriar Nafees edged one to de Villiers off Albie's brother Morne Morkel, Bangladesh slipping to 41-2.
Ashraful's woeful form continued, being caught at mid-on by Hamish Amla off Albie Morkel for nine. The under-fire skipper finished the series with just 17 runs from three outings.
Nazimuddin (20), who was looking to open up after hitting three boundaries, tried to go for a slog off Albie Morkel but only succeeding in holing out to Smith at mid-wicket.
Shakib Al Hasan also failed to rebuild the innings, with Botha claiming his wicket for 12 while Raqibul Hasan was run out, also for 12, with J.P. Duminy throwing to the wicketkeeper from covers.
Left-arm spinner Paul Harris cleaned up Dhiman Ghosh before Botha returned to have Razzak caught behind for nine.
The tail then folded without resistance, much to the disappointment of the crowd.
South Africa next head to India for a three-Test series starting March 26, while Bangladesh host Ireland for a one-day series.