Abraham de Villiers struck an unbeaten 69 to guide South Africa to a series-clinching seven-wicket win over Bangladesh in the second one-day international.
De Villiers shared an unbroken 119-run, fourth-wicket partnership with Jean-Paul Duminy as the Proteas chased down a target of 174 with 11 balls to spare.
The tourists had recovered from early trouble at 60-3 - Herschelle Gibbs, Hashim Amla and Graeme Smith all departing inside the first 17 overs.
Paceman Mashrafe Mortaza (1-27) trapped Gibbs (3) lbw in the fifth over and left-arm spinner Abdur Razzak (2-32) followed up with the wickets of Amla (16) and Smith (28).
De Villiers and Duminy (49no) took a steady, mainly risk-free approach to regain control of the run chase during a stand that spanned 31.3 overs and featured just four boundaries.
And de Villiers eventually brought up an 87-ball half-century - his 13th in one-day internationals - and sealed victory by slamming Tamim Iqbal (0-6) back over his head for six from the first delivery of the penultimate over.
Bangladesh had been bowled out for 173 in 48.1 overs after skipper Mohammad Ashraful won the toss and opted to bat first in Mirpur.
The only partnership of note was a Bangladesh record fifth-wicket alliance of 119 between Shakib-al-Hasan (52) and Raqibul Hasan (63).
Andre Nel took three wickets with the new ball to help reduce the hosts to 18-4 before Shakib and Raqibul instigated a painstaking recovery by staying together for 30.1 overs.
Man-of-the-match Nel finished with figures 4-27 from his 10-over allocation, while new-ball partner Charl Langeveldt also impressed with 3-31.
The series concludes in Dhaka on Friday when South Africa have the opportunity to complete a 3-0 whitewash that would move them top of the ICC's one-day rankings.