Captain Graeme Smith [ Images ] hit an unbeaten half century as South Africa [ Images ] 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 [ Images ] (40).

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

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 [ Images ] took four wickets, and Johan Botha [ Images ] 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).