South Africa posted 369-6 batting first, its highest score against Bangladesh in ODIs, and rolled out the tourists for 169 with almost 10 overs left unbowled at Buffalo Park.
And to add to the misery of the visitors, the players who came in new for South Africa displayed a fearless brand of cricket that caught Bangladesh off-guard.
But all-rounder Shakib al Hasan and No 7 batsman Sabbir Rahman formed a 77-run partnership for the sixth wicket to save the Tigers' blushes.
It was the biggest margin of victory by runs in a one-day worldwide anywhere for more than a year - since South Africa beat Ireland by 206 runs in September 2016. South Africa won the toss and elected to bat and scored a match-winning 369 for six in their allotted 50 overs.
Interestingly, Markram swops batting places with Temba Bavuma in the white ball format, meaning Bavuma will actually open the batting with Quinton de Kock.
A player was approached by bookie, confirms Najam Sethi
Earlier it was reported that Pakistan captain Sarfraz Ahmad was approached by a bookie for match-fixing which he turned down. The man who approached Sarfraz and the Pakistani skipper an offer is based in Dubai and is known to most of the players.
Dane Paterson was the pick of the Protea bowlers with 3/44 while Aiden Markram picked up 2/18 and Imran Tahir finished with 2/27. He has been replaced by JP Duminy as skipper in the T20s.
Du Plessis had added 151 for the third wicket with Aiden Markram, the debutant, when he had to be helped off the field, just nine short of his ninth ODI century. AB de Villiers took the field for some quick runs but could only put up 20 off 15 deliveries.
But the Proteas had a strong finish to match their strong start, with Kagiso Rabada unleashing some big shots - and three fours and a six - for his 23 not out from 11 balls.
Their innings was finally brought to an end with 169 runs on the board and 9.2 overs still remaining, which in turn handed South Africa a huge victory by a margin of 200 runs. For Bangladesh, Mehidy Hasan had the best bowling figures of two for 59.
