Rilee Rossouw smashed 109 and shared in the highest stand in T20 World Cup history with Quinton de Kock as the Proteas amassed 205-5 against Bangladesh in Sydney.
The pair came together after opener and captain Temba Bavuma again failed with the bat, out for two in the first over.
From there it was all South Africa with the pair putting on 168 for the second wicket, surpassing the 166 that Sri Lanka’s Mahela Jayawardene and Kumar Sangakkara made against the West Indies in 2010.
De Kock fell for 63 the next ball but Rossouw powered on, bringing up the first century of the Australian tournament and only the 10th ever at a T20 World Cup.
He was eventually out going for another big hit, ending a 56-ball knock in which he smashed eight sixes and seven fours. It was the fifth-highest score at a T20 World Cup.
The blitz put the Proteas on track for victory after their opening match on Monday against Zimbabwe in Hobart was washed out and the points were shared.
In contrast, Bangladesh opened their campaign with a nine-wicket win over the Netherlands and currently sit on top of Group 2 on two points with India.
But they have a poor record against top teams at World Cups, and have not won any of their seven T20Is against South Africa.
WIN: Braai kit, signed bat and signed jersey
Bavuma won the toss and batted first but the South African skipper was out cheaply again as his awful form continued.
Speedster Taskin Ahmed was coming off career-best figures of 4-25 against the Dutch and coaxed an edge with his raw pace that carried to Nural Hasan behind the stumps.
But that was as good as it got for Bangladesh as De Kock and Rossouw attacked Ahmed in his next over, pummelling 21 to assert their authority.
The pair were bludgeoned fours and sixes around the ground, bringing up their 50-partnership in four overs.
Their blitz was interrupted at 60-1 in the sixth over when light rain began falling. But they resumed after a 22-minute break, with no overs lost, and carried on where they left off.
Rossouw reached his 50 first, off 30 balls, with De Kock taking four balls longer.
They went on to demolish the Bangladesh attack, setting the new partnership record before De Kock was caught at long on off Afif Hossain for 63 off 38 balls.
Rossouw carried on and brought up three figures before ballooning a catch to Liton Das.
© Agence France-Presse