Andrew Strauss believes the form of his batsmen will make the ultimate difference in the one-day series with South Africa.

England took a 1-0 lead yesterday thanks to gritty performances from Paul Collingwood, who marked his England record 171st one-day international cap with his fifth hundred - an unbeaten 105 - and Jonathan Trott, his partner in a 162-run stand, who added 87.

The consequence was a seven-wicket win as England reached 252 for three with four overs to spare at Centurion, leaving Strauss to reflect on the qualities of the two players.

He said: "They always like the difficult situations - and Colly's played a lot of his best innings for England when our backs have been against the wall.

"As an opponent, I know you worry about players like that."

Trott, meanwhile, put in a major contribution on only his second ODI appearance.

"Trotty's form on this tour has been exceptional," added Strauss.

"We had no worries about him opening the batting - he's done it a lot for Warwickshire and is a quality player all round."

South Africa captain Graeme Smith knows his team are up against it to battle back into this five-match series against opponents who have now beaten them in six successive ODIs.

The absence of the injured Jacques Kallis - officially replaced by Herschelle Gibbs - hardly helped as his team could only muster 250 for nine from their 50 overs.

"It's up to us now as a group of players to work hard in Cape Town this week," he said, looking forward to the next match on Friday.

"We've got a good record there."

As for Kallis's injury, Smith acknowledged its significance.

"It's very big," he said. "There's a gap of experience around our group at the moment that needs to be filled.

"When you lose a guy that's played 280-plus one-day internationals and is a world-class all-rounder, it does make life a little bit more difficult.

"The rest of us are going to have to step up and fill the gap."