England 172 for 6 (Knight 85*, Osborne 3-31) trail Australia 331 for 6 dec (Elliott 104, Blackwell 54, Cameron 50) by 159 runs
Australia took firm control of the Ashes Test, reducing England to 172 for 6 on the second day, but Heather Knight kept the home side fighting and on track to avoid the follow-on after the middle order had been removed by Erin Osborne and the 17-year-old Holly Ferling.
Australia had made an bold declaration shortly before lunch on 331 for 6 - there is an incentive to win the Test with six points on offer in the new-style multi-format Ashes concept - after Sarah Elliott had reached a maiden Test hundred having been unbeaten on 95 overnight while Alex Blackwell contributed 54.
Ellyse Perry clubbed 31 off 24 balls and then struck an early blow when Arran Brindle was lbw in the ninth over. However, England formed themselves a decent platform as Knight and Sarah Taylor came together, but Taylor's dismissal for a sparkly 33 prompted a collapse.
Taylor became a maiden Test wicket for Ferling, who then claimed the key scalp of Charlotte Edwards lbw although the England captain was far from impressed with the decision. Substantial damage was then caused by offspinner Osborne as she claimed three wickets in the space of four overs to leave England tottering on 113 for 6.
England, though, resisted stoutly through the remainder of the day as Knight and Laura Marsh compiled a 36-over partnership worth 59. Knight hit 10 boundaries in her 225-ball innings while Marsh blocked through 114 deliveries to remain unbeaten on 13.
"It's a pretty good pitch out there and with Laura we managed to put together a partnership," Knight said. "Our team bats really low down the order so hopefully we can go out tomorrow, score a few more runs and then come hard at them with the ball.
"I decided to concentrate on what I was doing at my end and not worrying too much about the wickets we were losing other end. I feel good about my cricket at the moment. Whatever I'm doing is working so it's just about carrying that on. I think it's going really well.
"However we still need 10 more to avoid follow-on so that is our first objective and then there's the new ball in six overs so hopefully that will bring a few more runs."