By Martin Gough
BBC Sport at the Rose Bowl
West Indies captain Brian Lara admits his side must up the tempo after beating Bangladesh if they are to reach the Champions Trophy semi-finals.
The 138-run win began with a stand of 192 between Wavell Hinds and Chris Gayle, while Merv Dillon took 5-29.
Afterwards Lara said: "We are executing well. Chris and Wavell laid a solid foundation and Merv and Ian Bradshaw bowled excellently.
"This total was enough. Any team making 250 at the Rose Bowl is a good total."
South Africa's run rate of 3.41 is superior to the Caribbean side's 2.76, meaning a washout at the weekend when the two sides meet would see Graeme Smith's side go through.
Lara was buoyed by excellent catches by Darren Sammy and Dwayne Bravo, although Bradshaw missed two caught-and-bowled chances.
"It is the most important part of the game - if you are good in the field it gives you the edge," he said.
"In the summer we were not very good but on Saturday it could be telling in that area."
The West Indies skipper was pleased by the tournament format, which sees all of the top teams meet at the end of the group stage.
"The next week will have some exciting cricket," he said. "But it's going to be tough."
Lara offered words of encouragement for Bangladesh, who have only won two one-day internationals in the past five years.
"They are a very young team in international cricket and it will take them time.
"I think it is important they understand that each player needs to chip in. It is important to play as a team - you need a collective effort," he said.