England beat South Africa by six wickets in the fourth one-day international at Lord's yesterday to take a 2-1 lead in their five-match series.
Ian Bell hit 88 from 137 balls, with a six and eight fours, as England closed on 224-4, overhauling South Africa's 220-8 with 20 balls to spare.
Bell put on a second-wicket stand of 141 with Jonathan Trott, who was England's next highest scorer with 48.
Dale Steyn had South Africa's best bowling figures with 2-47, but the tourists were always struggling to defend a modest total.
England's bowlers did well to restrict South Africa after the Proteas had reached 100 for one.Spinner James Tredwell atoned for dropping two catches by claiming 3-35, while medium pacer Ravi Bopara took 2-34 and wicketkeeper Craig Kieswetter had three stumpings and two catches.
survived an early scare
Hashim Amla survived an early scare to finish as the tourists' top scorer with 45, while captain AB de Villiers made 39.
"It was a really good performance again," England captain Alastair Cook said. "Clearly, when you win the toss in those conditions, you want to make the most of it and I thought we did that, even though we didn't quite get the wickets early on. We hung in there and we got our rewards later."
De Villiers admitted his side had once again wasted a promising start.
"We had a good foundation with our openers but unfortunately the middle order failed again, so we'll have to have a look at that," he said. "The guys will just have to step up to the plate, including myself. We keep getting in and we're not converting to big numbers and that's the only issue at the moment."
After winning the toss, England chose to bowl in overcast, damp conditions.
Amla was dropped - for the sixth time this summer - when Tredwell put down a slip catch off Steven Finn with the batsman on 4.
Smith was on 26 when he slashed Finn and was dropped by Tredwell at first slip, who may have been distracted by Kieswetter's dive.
Amla hit the first six of the match when he smashed Jade Dernbach back over his head, but England belatedly broke through in the 20th over when Smith tried to pull Dernbach and was caught behind for 29.
Bopara then bowled Amla and Tredwell deceived JP Duminy, who charged down the pitch and was stumped for 18.