Australia 473 and 82 for 0 (Litchfield 41*, Mooney 33*) lead England 463 (Beaumont 208, Sciver-Brunt 78, Knight 57) by 92 runs
In the meantime, McGrath - the pick of Australia's seamers with 3 for 24 from 12 overs - had dismissed Sophie Ecclestone lbw, bowled Kate Cross for a second-ball duck with a gem that nipped back and crashed into off stump and had Lauren Filer caught behind trying to slash at one that moved away sharply on her.
She resumed unbeaten on 100 on Saturday's third morning at Trent Bridge, having sprinted for a second run to bring up her maiden Test hundred late the previous evening. England were still 255 runs in arrears but, after a watchful start, she and Sciver-Brunt set about eating into the deficit with a boundary-rich first session.
That was after Darcie Brown thought she had Sciver-Brunt out lbw for 41 with the first ball of the day before England successfully reviewed, replays showing the ball was missing leg stump.
Australia conceded just one run off the first three overs of the day but then Beaumont picked off three fours in one Brown over, beautifully timed past mid-off, eased through the slips cordon and then pulled through wide mid-on.
Sciver-Brunt raised her fifty by exquisitely timing a Brown delivery to the boundary through deep backward point and she helped herself to three in a row off Sutherland, either side of the pitch.
Surprisingly, given that Gardner and Alana King had caused England some difficulty late on the second evening after Australia's seamers had struggled throughout Friday, stand-in captain Alyssa Healy left it until well into the second hour to re-introduce her slow bowlers. Off-spinner Gardner struck with her ninth ball of the morning, a faster, flatter delivery outside off stump which found Sciver-Brunt's outside edge as she stepped back to cut, misjudging the length and feathering to Healy behind the stumps.
England were 288 for 3 but leg-spinner King was extracting some impressive turn as lunch neared. Sophia Dunkley took 18 balls to get off the mark and was not out on 7 as England went to the interval having added 90 runs for the loss of just one wicket. Australia delayed taking the second new ball and were rewarded when Gardner struck again, Dunkley playing across the line to a ball which clattered into off stump to be out for 9 off 51.
Beaumont had survived the previous evening when she struck a King delivery onto her boot and Litchfield wasn't awarded the catch at short leg. Today, Beaumont was adjudged lbw on 152 when she was rapped on the pad attempting to sweep King, but she reviewed and was vindicated when replays showed the ball had pitched fractionally outside leg stump.
Danni Wyatt made her Test debut after 245 white-ball internationals and played a typically fast-paced innings. She scored her first runs steering the second ball she faced, from King, through deep cover to the fence and struck seven boundaries on her way to 44 at a strike rate of 89.79. But Brown took the second new ball after 99 overs and sent down a couple of eye-catching bouncers. She had Wyatt all at sea with a length ball angling in that the batter lost sight of and, next delivery, Wyatt sent a catch straight to Jess Jonassen at second slip.
The fifth ball of Brown's over jumped off a length at Amy Jones, but Jones responded by dispatching the next delivery through deep midwicket with a perfectly timed pull. Jones managed two more boundaries before Ellyse Perry had her out to a leading edge, swallowed by Sutherland at mid-on but Beaumont just kept marching on.
Valkerie Baynes is a general editor, women's cricket, at ESPNcricinfo