Captain Graeme Smith [Images] hit an unbeaten half century as South Africa beat Bangladesh by seven wickets in the third and final one-day international on Friday, to sweep the series 3-0.

Scorecard: 

After bowling out Bangladesh for 143 in 42.5 overs, South Africa comfortably reached 147 for three in 34.2 overs, losing opener Herschelle Gibbs [Images] (10), Alviro Petersen (24) and AB de Villiers (40).

With the series victory, South Africa reclaimed the top spot in the world one-day rankings ahead of Australia.

Smith's unbeaten 68 was his 36th ODI half century. He faced 94 balls and hit three boundaries and three big sixes, including the winning shot.

Smith passed 5,000 runs in one-dayers when he reached 52.

Earlier, Albie Morkel took four wickets, and Johan Botha three to help South Africa bundle out Bangladesh for a paltry total.

Bangladesh made a sluggish start after winning the toss with opener Tamim Iqbal caught behind by de Villiers for eight in the 10th over off Albie Morkel, who finished with a career-best 4-29.

Opener Shahriar Nafees top-scored with 25, followed by Farhad Reza with an unbeaten 20 and Nazim Uddin (20).