Both teams are aiming for victory to claim the remaining semi-final spot and join champions Australia, New Zealand and Sri Lanka.
South Africa have six points ahead of their last Super Eights game while England, on four points, need to win to make sure their final game against hosts West Indies is not rendered inconsequential.
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Smith's team have lost their tag as top-ranked one-day team after their shock 67-run defeat against Bangladesh and then a five-wicket loss against New Zealand on Saturday after their batsmen failed on slow pitches in Guyana and Grenada.
"I'm pretty sure it's going to be an explosive game," Smith told a news conference on Monday.
"Again, adapting is going to be a key tomorrow," he said, referring to the lively Kensington Oval pitch.
"It (pitch) does seem to have a little more pace and bounce which will probably suit us in a lot of ways.
"We just have to find our feet early on and get into the game as soon as we can."
However, England have better knowledge of the pitch after scoring a four-wicket win over Bangladesh on it last week.
Despite South Africa's problems, Smith denied the team, dubbed World Cup chokers, were again succumbing to pressure.
He also played down controversy over a late-night drinking session by some players after the New Zealand defeat.
"If we win tomorrow we secure the semi-final," he said. "It is important to just concentrate on the cricket.
"We haven't played to our potential," he said. "Three games left, if you win those you win the World Cup."
He said the wicket of in-form England batsman Kevin Pietersen would be crucial.
Smith has had a poor personal relationship with Pietersen, who migrated from South Africa to further his playing career, but said the focus would remain on winning the game.
"We've had our run-ins and tomorrow is an important day of cricket," he said. "He is an important cog in that England set-up. How we knock him over is going to be important.
"(But) it's a game we want to win," he said. "As far as his cricket abilities go we have respect for that."
England skipper Michael Vaughan hoped his team could repeat the late surge to win this year's tri-series in Australia.
"The last four games in Australia, we were outstanding," he said. "With the last four games left, if we produce that kind of performance again, come back from not being very good, that would be a great effort."
The seven-week World Cup culminates in the April 28 final in Barbados.
