Faf du Plessis. Photo: Jason Cairnduff/Reuters

South Africa hope to live up to their reputation as the world's top-ranked one-day international side at Southampton on Saturday after blowing away "cobwebs" in their series-opening defeat by England.

Victory put England 1-0 up with two to play and was a shot in the arm for Eoin Morgan's men ahead of next week's start of the Champions Trophy on home soil.

But South Africa batsman Faf du Plessis said the tourists were determined to avoid a repeat of the "silly mistakes" that had cost them dear in a 72-run reverse at Headingley on Wednesday.

"We were disappointed with the way we played at Leeds – that's probably the most mistakes we've made in a game for a while," du Plessis told reporters on Friday.

"But England put you under a lot of pressure, and you have got to make sure you are on top of your game and transfer the pressure back on to them."

Du Plessis and opener Hashim Amla gave South Africa a shot at chasing down England's total of 339 for six at Headingley. But they both fell in quick succession and a promising position of 145 for one became a score of 267 all out in 45 overs for AB de Villiers's side.

Photo: Jason Cairnduff/Reuters

"We've played some really good cricket over the last while, so that last game was a bit of cobwebs," added du Plessis. "We made some silly mistakes tactically, so hope we can do better this time."

But for South Africa, as is the case with England, a series win now is nothing compared to a Champions Trophy triumph in a few weeks' time, with the tournament featuring the world's top eight ODI teams.

"It's about making sure you are gearing up to play your best cricket when the tournament is at its peak," explained du Plessis.

"At Leeds we got ourselves in a position where we could have possibly won the game with the bat... and with our strong middle order we should have done better.

"From a bowling point of view we made a lot of silly mistakes and gave the English batsmen too many free runs," he added.