Coach Andy Flower wants England to display a greater ruthless streak in one-day cricket and highlighted his own on Saturday when he insisted he would not have reprieved Angelo Mathews.

It was captain Andrew Strauss' decision to recall Mathews following his collision with Graham Onions, going for a second run, which drew as much attention as England's winning performance against Sri Lanka in the Champions Trophy on Friday night.

But the act of sportsmanship would not have been replicated had former Zimbabwe player Flower been in charge on the field.

"I would definitely have not recalled him," said Flower, ahead of Sunday's second Group B contest against hosts South Africa.

"But Strauss is a good man and I trust him completely.

"He made his decision and I back him on that, I just wouldn't have done it myself. I would have sent the batsman on his way. He ran into the bowler. Simple deal."

Victory over South Africa in the day-night encounter at Centurion would send England into the final four of the mini-World Cup at the earliest opportunity.

It will be a tall order but England have made a habit recently of winning when not fancied.

They arrived at the competition as one of the outsiders, given their one-day thrashing by Australia, but humbled in-form Sri Lanka by six wickets with plenty to spare.

"Look, we are huge underdogs going into tomorrow," said Flower.

"Everyone realises that. It doesn't mean we can't win the game - we were underdogs going into the game against Sri Lanka, we were underdogs going into the Ashes series - but we will have to be right on top of our game to do so."

Flower went on a scouting mission to assess the pitch in Pretoria this morning and discovered it to be excessively dry.

That will encourage turn and increase the chances of leg-spinner Adil Rashid being drafted into a winning XI.

England have never won a global tournament and their chances of doing so here have been made harder by the absence of Kevin Pietersen and Andrew Flintoff, their two star players, through Achilles and knee injuries respectively.

Pietersen hit a stunning hundred the last time England played South Africa at Centurion in 2004-05.

He is currently in Johannesburg on a social engagement but his chances of a return for England's winter tour, which begins on November 1, are yet to be determined.

"I spoke to KP the day we left England and he was sounding a lot more positive about the state of his leg," said Flower.

"I haven't spoken to him since he has been here but I will do soon.

"We hope he is going to be ready for the start of the South Africa tour but we don't know yet."

Without Pietersen and Flintoff, England lack firepower in the middle-order but it has opened up opportunities for others.

Of the missing two, Flower said: "The players are not giving that a moment's thought. Neither am I.

"When those guys come back it will strengthen our side, there is no doubt about that but we don't discuss it.

"We will look at that situation when it arises, when they come back.

"At the moment this is our 15 and they have got the responsibility to win the games for England."

Paul Collingwood provided England's chase of 213 against the Sri Lankans with real impetus, cracking three sixes in his 46, while Owais Shah hit 44 and Eoin Morgan an unbeaten 62 to signify a return to form for the misfiring batsmen.

However, the revamp of the top six, which resulted in Shah's promotion to number three, also included the axe for Ravi Bopara.

It is the second time in a couple of months that Bopara, who began 2009 with three consecutive Test hundreds, has paid the price for poor form, having been left out of the final match of the Ashes.

For Flower it also meant having to tell his former Essex team-mate his fate.

"The difficulty in a situation like that is it does effect someone's career," Flower said.

"So it is an important decision but, to be honest, in the context of balancing our side and what we needed for that game, it wasn't that difficult a decision.

"He has had a lot of chances, hasn't taken the chance, so he lost out.

"Whether he gets that chance again in this tournament, I don't know."

Bopara is perhaps best described as a rough diamond that has yet to be smoothed for international level.

"He's very talented, and he's a good friend of mine, actually, but the polishing has to be done by himself," Flower warned.

"We have invested a lot in Ravi Bopara - a lot of time and opportunity.

"He's a hard worker, there's no doubt about it, he works very hard but results on the park are what count and in his job it is runs."