Eighty wickets in eight matches, including the warm-up games, and South Africa's bowling can rightly be called the best in the competition to date. No team, except India on a batsmen's paradise in Nagpur, has scored more than 250 against them.

The wickets have come from everywhere: the two menacing fast bowlers who were rested in Mirpur - Dale Steyn and Morne Morkel - the offspinner Johan Botha, the left-arm spinner Robin Peterson, the new legspinner Imran Tahir and now even the reserve bowler - Lonwabo Tsotsobe.

"I feel very chuffed about it," Tsotsobe said of his 3 for 14 Man-of-the-Match performance against Bangladesh. "It woke me up and said to me that I have to work harder each day. I am still part of the team."

Those were the words that made Graeme Smith's smile, already wide as the room itself, even wider. South Africa have been trying to build a team culture that stands out from the ethos they previously had - of being like a boarding school, where authority comes from the top and the rest must follow suit - to a more embracing one where every member of the team is important. The result of that is that when those on the fringes are called on to perform, they don't feel as though they need to step into massive shoes; they simply get on with their job.

"From the start we've always been a squad," Smith said, when asked how pleasing it was that Tsotsobe had come in and performed with such aplomb. Tsotsobe was the leading wicket-taker in the recent home one-day series against India and, on the face of it, it looked as though he was being left out of side at just the wrong time, when he was trying to establish himself as the vital third prong in the seam attack. "It was very difficult for us to leave Lopsy out, he has been very good for us," Smith said.

It turned out to be somewhat of a stroke of genius to rest Steyn and Morkel and bring in Tsotsobe and Wayne Parnell, the two left-armers who sat on the sidelines for the first five group games. The hunger of the two pacers had been building for over a month. They had seen the way the West Indies pace attack had torn through the Bangladesh line-up and they knew that with a fragile confidence base they may be able to do the same, especially with the number of left-handers in the Bangladesh line-up.

It was the ideal way to bring Tsotsobe and Parnell into the tournament, because with South Africa comfortably through to the quarter-finals, it would have been easy for the team to slack off. Bringing in two squad members who would not have thought of slacking off at all was the master move. Smith recognised the team needed to find that extra fire from within. "We could have easily gone through the motions when we had them five down," he said. "But it was good to see the commitment of the guys."

Instead of releasing the brake when they had Bangladesh at 36 for 5, they slammed on it harder and that's what Smith was proud of. "It was good to see the guys putting their bodies on the line." The fielding was their way of squeezing the life out of the Bangladesh batsmen. It seemed like a brutal way to handle a team that were clearly under the cosh and that were going to surrender at any point. Instead of letting Bangladesh admit defeat on their own terms, South Africa wanted to dictate proceedings.

That's the best preparation for the quarter-finals, where South Africa's real test begins. They've talked about taking it one game at a time and not thinking too far ahead of themselves. Now, the time they've been preparing for with small steps has come. It's important that South Africa don't change their approach too drastically, since it has served them so well. "We have to just carry on the way we have," Smith said "We've met each challenge as it comes."

The Bangladesh challenge was met with the brute force that Smith said the team used to be about and the street smartness that he said they'd gathered in the last few years about playing sub-continent sides. South Africa are changing tactics and strategies with each game, not for the sake of it, but to be able to directly challenge the opposition. That's why Smith is not concerned about who they meet in the next round. "I've said before that if you are to win this tournament, you have to beat whoever you play, so we are not thinking about it."

Firdose Moonda is ESPNcricinfo's South Africa correspondent