Bangladesh was able to rack up a total of 330 runs with the Shakib Al Hasan and Mushfiqur Rahim's knock of 75 and 78 runs, respectively.
Before the World Cup, Bangladesh also clinched the Tri-nation series after beating West Indies and Ireland. West Indies and Ireland struggled a lot in the series as both failed to overpower Bangladesh even once in the series.
Consequently, Bangladesh entered in the premier tournament with a lot of confidence and they continued to show their impeccable form to vanquish South Africa.
Hasan, who atop the ICC ODI All-rounder rankings, expressed his confidence in the squad and stated that they have the skill to beat 'big teams'.
"Building up to this World Cup, we knew what sort of challenges we might face. So we prepared ourselves well. We were in Ireland, where we played really well against West Indies and Ireland.
That gave us a lot of confidence and belief. There are so many things to prove in this tournament, and we were upto the challenge. The boys were confident, but at the same time, they were relaxed. They knew we have the skill to beat big teams," ICC quoted Hasan as saying.
Hasan feels that they have improved a lot since they defeated India and South Africa in the 2007 edition of the ODI cricket showpiece and said that crowd's expectations have also increased many folds from them.
"It's been 12 years, so our cricket has come a long way forward. At that time, if we play well, that was good enough for the crowd and for us.
But now, they are not satisfied with defeat to any other team. This is the expectation level we've got in these 12 years. I'm very happy, but this is just the start of the tournament," he said.
Bangladesh will now face New Zealand for their second World Cup encounter on June 5.