Australia recovered from 1-0 down in the series
Australia came from behind to beat England 45-43 at the O2 Arena in London and clinch the Test series 2-1.
Australia goal shooter Kate Beveridge shot 23 from 32 attempts as the Diamonds recovered from a nine-goal deficit in the third quarter.
England, who dominated for most of the game, also led 23-17 at half-time.
The hosts won the opener 41-40, the first time they had beaten Australia in a Test since 1981, before Australia levelled the series with a 53-48 win.
"It's incredibly disappointing because I think this is the first time that the whole squad have really believed we can take Australia," said England co-captain Karen Atkinson.
England head coach Sue Hawkins added: "When we were nine goals up we should have built from that margin.
"We have to go back and look at what it was: was it that they stepped up? Or that we allowed them to step up? My feeling is we allowed them to step up."