Third women's ODI, Shenley:
England 185 beat South Africa 108 by 77 runs
England had too much firepower for the South African batting line-up
Sussex team-mates Laura Marsh and Holly Colvin bowled England's women to a 77-run victory over South Africa in the third match of their one-day series.
Marsh took 4-19 and Colvin 3-20 at Shenley as England took a winning 3-0 lead in the best-of-five series.
Batting first, England posted a total of 185 thanks to Lydia Greenway's determined 61 not out off 101 balls.
But the tourists slumped to 71-7 in reply and were all out in the 43rd over as Marsh cleaned up the tail.
"I'm delighted with the way the girls have played so far. We had an awesome day at Lord's last Friday and then to take the series at Shenley is just fantastic.
"We just need to continue in this form as we head into the last couple of games of this series and the NatWest Women’s International Twenty20 series," captain Charlotte Edwards said.
"We've still got a tough series to come against India this summer, so we'll continue to work hard and hopefully take this form into that."
England made two changes to the side which won by 225 runs at Lord's as Marsh and Ebony Rainford-Brent came in for Isa Guha and Beth Morgan.
Perhaps more surprisingly, they decided to separate openers Caroline Atkins and Sarah Taylor after their record stand of 268 last Friday to give Rainford-Brent a chance at the top of the order.
She did not waste the opportunity, collecting nine boundaries in an attractive 45 before being stumped off left-arm spinner Charlize van der Westhuizen, who bowled an excellent spell of 4-30.
But Atkins and Edwards both fell cheaply and Jenny Gunn was lbw third ball for nought as England failed to match their Lord's fluency.
And it was Colvin, batting at number 10, who provided vital support for Greenway as she guided the team to a defendable total.
Katherine Brunt made short work of Daleen Terblanche with the new ball and Gunn redeemed herself with two wickets as the tourists stuttered at the start of their innings.
Alicia Smith made 30 but spinner Colvin followed van der Westhuizen's lead earlier in the match by working her way through the middle order.
Sunette Loubser hung around for half an hour to make 22 in the lower order but she was eventually bowled by Marsh, who then removed Ashlyn Kilowan in similar fashion to end the match to finish with her best return in a one-day international.