England 280 (Beaumont 70, Knight 62, Perry 3-59) and 2 for 206 (Knight 79*, Elwiss 41*) drew with Australia 9 for 448 dec (Perry 213*)
England's captain Heather Knight held firm as the visitors scrounged a draw from the inaugural day-night women's Test, leaving the Ashes in the balance ahead of the Twenty20 leg of the series.
On a wearing pitch at North Sydney Oval, England were under pressure throughout the final day, particularly after Amanda Wellington's reprise of Shane Warne's epochal legbreak to Mike Gatting when she spun past Tammy Beaumont with a delivery that pitched outside leg stump before biting back to take the top of the off stump.
It was a moment to savour, but Wellington's inability to follow it up with a rush of wickets was largely down to Knight, the embodiment of calm temperament and sound technique in an innings that ensured England would not be overwhelmed following Ellyse Perry's epic double-century on days two and three.
Starting the day in considerable deficit, Beaumont and Lauren Winfield played soundly early on to avert the prospect of a collapse, but found life difficult against Wellington and her hard spun legbreaks.
Beaumont's exit was of the kind that can send shudders through a dressing room, and it was to the credit of Knight and Georgia Elwiss thst they were not dislodged once Winfield had been pinned lbw on the front toe by an inswerving yorker from Tahlia McGrath shortly after the start of the second session.
So securely did Knight occupy the crease that Australia's captain Rachael Haynes was compelled to accept the inevitability of a stalemate around an hour before the scheduled close of play, England having forged into a lead that made them safe from defeat.
This in turn means that the series remains open ahead of the final three T20 fixtures, the first of which will take place at North Sydney on Friday. Perry was rightly named Player of the Match for her double-century.
Daniel Brettig is an assistant editor at ESPNcricinfo. @danbrettig