The final match, which now amounts to a decider, takes place at Chittagong on Wednesday.
During the course of this year Bangladesh have won home series against Zimbabwe, Pakistan and India and also beat England at the World Cup to effectively eliminate the latter from the tournament. They also took the eventual finalists, New Zealand, all the way in the same tournament.
With this performance Bangladesh have guaranteed their qualification for the 2017 ICC Champions Trophy in England.
Such was the freedom with which the pair batted that it was hard to believe that both side’s innings had been played on the same pitch.
The South Africans were unable to put any decent partnerships together and for the first time ever against Bangladesh failed to bat out their 50 overs after winning the toss.
In the circumstances there were few even reasonable performances by the Proteas. Faf du Plessis (41 off 64 balls, 3x4) and Farhaan Behardien (36 off 44 balls, 2 fours and a six) were the main contributors to the indifferent total with the latter deserving credit in holding the lower order together as they added 62 for the last four wickets after the first six had fallen for 100.
Kagiso Rabada was again the standout South African bowler, giving hope to his side when he took two wickets with the new ball in his opening spell.
He also had his first opportunity to bat at international level and, although he only made 10 runs, he produced strokeplay of a quality that suggests he could develop into the all-rounder the Proteas need in ODI cricket by the time of the next World Cup.
Bangladesh bowled with an intensity they had lacked in the previous tour matches and the inclusion of Rubel Hossain, who had an excellent World Cup, made a notable difference.