Once again, England produced a fine performance under Kevin Pietersen's captaincy to wrap up victory in the NatWest Series with a 126-run defeat of South Africa at The Oval.

The result put England into an unassailable 3-0 lead in the series with only two matches remaining, at Lord's and Cardiff. The victory was build on a solid foundation laid by Ian Bell (73) and Andrew Flintoff (78 not out), who took England to 296-7, a total South Africa were unable to challenge.

The tourists never threatened to launch a plausible reply, and Samit Patel (five for 41) - who had shared an important 74-run sixth-wicket stand with Flintoff in his maiden ODI innings - took the bowling honours in a hapless 170 all out, with more than seven overs unused.

Samit Patel, who took 5-41, pegged South Africa back with his left-arm spin. The South African chase flickered only briefly when Albie Morkel hit Patel for two sixes in an over but having planted him into the stands the batsmen offered a low return catch that Patel gobbled up.

England are now chasing only the second 5-0 series win in their history after they triumphed over Zimbabwe by the same margin in 2001-02. A 5-0 series win would put England second in the one-day world rankings.

Flintoff, adding to the 78 he made in the first game at Headingley, and relishing his role at number five put on a free-scoring partnership of 74 for the sixth wicket with Patel that took the game away from the South Africans.

His recent form with the bat is another triumph for new captain Pietersen who has promoted the all-rounder up the order and persuaded Steve Harmison, a crucial figure in this series, out of one-day international retirement.

Flintoff survived a nasty blow to his temple on 38 when he was late on pulling a Morkel bouncer but recovered to hit nine fours and a six. The pick of the South African bowlers was Johan Botha who took 2-35 from nine overs with his spin.

After being put in England's Matt Prior played and missed during the early overs but found his range when he clubbed 14 runs off Makhaya Ntini's second over including a six over long on from a free hit.

Ntini's first five overs disappeared for 47 but stand-in captain Jacques Kallis forced a breakthrough when Morne Morkel had Prior caught off a top edged pull that Herschelle Gibbs ran round to catch. Ntini looked a tired bowler at the end of a long tour as he conceded 68 runs in nine overs.

Bell, looking for a second one-day international hundred, had a close shave when he was nearly run out on 73 but fell without adding another run when he was leg before to Johan Botha trying to turn the ball to midwicket.

Wickets fell steadily and England were 182-5 in the 35th over when Paul Collingwood was out but Flintoff and his tail end partners managed to eke out another 114 from the last 15 overs before Pietersen's bowlers, with Patel to the fore, squeezed the South Africans out of the contest.

Pietersen challenged his side to win the remaining two matches after clinching victory in the series.

"We've come in (to the series) as underdogs for sure but we've hit our straps in every department," he said. "The boys have been magnificent, it's an exciting place to be, the England dressing room.

"I'm a very privileged person. The blokes in the dressing room have done an amazing job. But we want to improve and we want to try to win it 5-0 if we can.

"I want the guys to enjoy this victory and turn up on Sunday ready to go 4-0 up. We need to carry on and keep going."

Kallis, who has taken over from the injured Smith, admitted his side were very much second best.

He said: "We're not playing good cricket but England are playing unreal cricket, they're one of the better one-day sides and they're outplaying us in all departments.

"We've lost a few key players, but the guys who are there now are not performing to the level they need to. We lost the game in the first 10-15 overs today and put ourselves under pressure.

"Were not firing on all cylinders and it's hard times for us at the moment."