England 235 for 8 (Knight 127*) trail Australia 337 for 9 dec (Lanning 93, Haynes 86, Gardner 56, McGrath 52, Brunt 5-60) by 102 runs
Heather Knight almost single-handedly kept England afloat in Canberra with a magnificent century which frustrated Australia's attempts to secure a big lead in their bid to retain the Ashes.
England were in danger of not saving the follow-on when they lost their eighth wicket with 19 runs still needed, but Sophie Ecclestone stayed with Knight as she brought up her second Test hundred and then carried her team past the initial target of 188. The 127 that Knight closed on equaled Smriti Mandhana as the highest innings by a visiting female batter in Australia.
To emphasise the domination of Knight's performance, the next highest score in England's innings was Ecclestone's vital, unbeaten 27 at No. 10. The pair took advantage of the extra hardness of the second new ball and some weary bowlers with 37 runs coming off the last seven overs of the day. The ninth-wicket stand extended to 65 and took them through to the close with the opportunity to further eat into Australia's lead. After two days, Knight had been on the field for all but 2.1 overs of the match.
With bowling again removed as an option for Australia, the onus may come onto what size of target they want to set England although the visitors will hope to apply pressure with the ball. The forecast is not good for Saturday which may cut into the time available and Australia do not have the same urgency to win the Test given they hold the points lead in the series.
It was a wonderfully-constructed hundred from Knight, whose previous Test century came at Wormsley in 2013 when England were in a similarly difficult position. Initially the innings was studded with superb cover drives, one which took her to her fifty, then her full array of sweeps were on show against the spinners. She also struck her first Test six when she sent Ashleigh Gardner over deep midwicket.
Australia's bowling success was shared around with the seamers getting the ball rolling, including maiden Test wickets for Darcie Brown and Annabel Sutherland, before the spinners started to chip in which included a first scalp for Alana King who sent down a long spell of well-controlled legspin during the afternoon and evening.
Meg Lanning had declared when Australia lost their ninth wicket with them adding just 10 runs to their overnight total. Katherine Brunt claimed the two wickets, including a fantastic delivery to take the top of Sutherland's off stump, which completed the third five-wicket haul of her career.
Brown soon provided the breakthrough with her first Test wicket when she lured Lauren Winfield-Hill into a drive which was neatly held by Beth Mooney at second slip.
Ellyse Perry, during a seven-over opening spell, then found a way past Tammy Beaumont as the tactics of targeting the pads paid off when a delivery nipped back to beat the inside edge and take the back leg. Beaumont reviewed but it was three reds.
However, despite the two wickets Australia could have bowled better overall before lunch with the batters not made to play often enough. Brown operated with good pace but was too wide either side of claiming her wicket while Tahlia McGrath didn't settle from either end across two spells and also had no-ball problems, of which she was not alone among the pace bowlers.
But Australia continued to take key top-order wickets against an England line-up that had gone in a batter light compared to their previous Test against India last year. Sutherland found the inside edge of Nat Sciver early in the second session with a delivery that nipped back sharply to claim her first Test wicket and when Sophia Dunkley chopped against Perry it was 79 for 4.
Knight continued to stand out, peppering the off side with a series of well-timed drives, to extend a fine record at Manuka Oval but struggled for support. Amy Jones had briefly offered a counterattack in a period that brought England four boundaries in six balls, but she then got a top edge against a short-of-a-length delivery and Brown took a running catch from mid-on.
King's first Test wicket came when she beat Brunt with a delivery that skidded on and she also found significant turn with her leg-break which suggested a big role to play if Australia are to force victory.
Debutant Charlie Dean hung around for 40 balls alongside Knight before picking out deep midwicket the delivery after Rachael Haynes had almost managed to kick the ball up and take a parried chance at short leg. Anya Shrubsole played a poor stroke against the lightly-bowled Jess Jonassen, but there was no shifting the England captain in one of the great Ashes displays.