Australian opener Beth Mooney smashed the first century in women's Twenty20 internationals in her country, but counterpart Danielle Wyatt hit the second as England claimed a stunning victory in the Ashes finale.
England snatched an 8-8 draw in the multi-format series in consolation for the home side retaining the urn last week, chasing down a record 178 for a four-wicket win in the third T20 on Tuesday.
The victory in Canberra extends a winless Australian T20 series streak at home dating back to November 2014, leaving them to rue four dropped sitters in the field as Wyatt struck 13 fours and two sixes for 100 runs off 57 balls.
The match's 359 runs total was the most in a women's T20, one of a number of records at Manuka Oval.
Left-handed opener Mooney was scintillating with 19 fours and a six in her 70-ball innings of 117.
Only injured captain Meg Lanning had previously hit an international T20 century for Australia, making 126 against Ireland in 2014 in Bangladesh.
The performance bettered Mooney's match-winning unbeaten 86 when Australia clinched the Ashes on Friday night in the opening T20 at North Sydney Oval, sparking bittersweet emotions.
"I'm not sure whether to laugh or cry, really," she said.
"It's not all doom and gloom. We've won the Ashes and, especially coming off the disappointment of losing the World Cup, I think we've still got a lot of things we need to celebrate."
Mooney and Alyssa Healy produced an opening stand of 59 before Healy was out for 19, thanks to a fine diving catch by captain Heather Knight.
Mooney reached her half-century off 38 balls before No.3 Elyse Villani was bowled by spinner Sophie Ecclestone for 16.
Mooney, supported by Ellyse Perry (22), finished the innings superbly with four boundaries in the final over off Anya Shrubsole for the hosts to end on 2-178.
England started the chase poorly when opener Tammy Beaumont and Sarah Taylor were both caught in the in-field off spinner Jess Jonassen to be 2-16 at the start of the third over.
The visitors were handed their first reprieve when Wyatt skied Molly Strano, but wicketkeeper Healy was unable to hold an easy catch.
England's bid for quick runs again came unstuck when Natalie Sciver was removed for seven, run out by a Villani direct hit from mid-off in the fifth over.
Wyatt and Knight (51 off 37) fought back with a 139-run partnership, aided by easy dropped catches by Strano at short fine leg, deep mid-wicket Megan Schutt and Healy again.
Knight's dismissal was quickly followed that of Wyatt and Brunt.
But England would not be denied in winning with an over to spare to take some of the gloss off victorious Australia, whose two one-day and sole T20 victories, and a drawn Test, were enough to retain the trophy.
Knight was named player of the Ashes after scoring 335 runs at an average of 55.83.
RECORDS BROKEN IN THIRD WOMEN'S ASHES T20
* Most runs in a match (359)
* Highest successful run chase (England)
* Most runs by an opener (Beth Mooney - 117 not out)
* Highest score in a losing team (Australia)
* Highest score by an Englishwomen (Danielle Wyatt - 100)
* Highest score in a run chase (Wyatt)
* First international women's T20 with two centuries
* Most fours in an innings (Mooney - 19)
* Most runs in a two-team series (Mooney - 220)
* Highest individual score in Australia (Mooney - 117 not out)
