Fourth women's Twenty20 international, Canberra:
England 144 (19.5 ovs) beat Australia 131-6 (20 ovs) by 13 runs
Marsh gave the England innings impetus at the top of the order
England remain on course for a whitewash in the five-match Twenty20 series against Australia after a 13-run victory in Canberra put them 4-0 up.
The tourists were all out for 144 with one ball of their innings left, Laura Marsh firing five fours in 43 from 28 balls and Laura Greenway adding 28.
Leah Polton hit three fours in 32 for Australia but spinner Holly Colvin (2-25) restricted them to 131-6.
The final match of the series is also in Canberra and takes place on Tuesday.
England captain Charlotte Edwards chose to bat first on a flat Manuka Oval pitch and she hit three fours in a breezy 15 from eight balls until she was run out in the third over.
Marsh maintained the momentum until she departed in the 10th over and even though four wickets fell for six runs in two overs, including a golden duck for Fran Wilson, England were still able to post a competitive total.
Australia looked set to overhaul it, however, after racing to 40 without loss after four overs.
But Poulton was dismissed with the final ball of the eighth over and Colvin struck twice in consecutive overs, dismissing Australia captain Alex Blackwell first ball as Australia fell short of their target.
Following the T20 finale, the teams move to Sydney for the one-off Ashes Test at the Bankstown Oval, which starts on 22 January.
"England currently hold the Ashes and we have one chance to get them back so we will be playing some good attacking cricket to do everything we can to win them back," Blackwell said.
"We've got half the squad from New South Wales so we're all really looking forward to getting back home and putting on a good show.
"We've played some good one-day and Twenty20 cricket so far but there is no doubt an Ashes win would be the highlight of the summer for us."