An unbeaten Steve Smith will have to defy England's fearsome attack and fickle weather if he is to drag Australia to victory at Lord's, where rain ruined day three of the second Ashes Test.
The tourists resumed at 30 for 1 and made a bright start under dark skies and artificial light, only to lose three wickets for 11 runs in a collapse ignited by debutant Jofra Archer.
Smith dug in during the chaotic session to help Australia reach 80 for 4 at lunch, when England's lead was 178 runs.
The meal break started midway through what would have been the final over of the morning session because of rain and the covers remained in place until play was abandoned at 5.20pm (local time).
Five sessions of the match have now been washed out after an anticlimactic opening day in which no play was possible.
It means a draw is the most likely outcome.
But a magnificent opening spell from Archer has given England sniff of a series- levelling victory, while Smith's presence at the crease will always embolden Australia.
Smith is 13 not out from 40 deliveries.
Matthew Wade, fresh from a century in his Test recall at Edgbaston, is yet to get off the mark but also showed great composure while facing 23 balls.
Archer, Stuart Broad and Chris Woakes snagged a wicket each in bowler-friendly conditions on day three but failed to unsettle Smith.
Smith, the difference between the rivals during Australia's series-opening win in Birmingham, did well to negotiate a particularly tense opening burst from Archer and Woakes.
Australia scored a single run in a six-over stretch that featured the dismissals of Cameron Bancroft and Usman Khawaja, who departed in the space of four deliveries.
Smith, knowing a decent first-innings total will be Australia's best hope of taking a 2-0 series lead, exhibited sheer determination rather than the free- scoring style of his preceding ton.
There was an exaggeration to Smith's tics that hinted at the match being in the balance, with the former skipper swishing his bat when shouldering arms and bounding around the crease like a West End performer.
The edginess of the situation was also highlighted by some miscommunication between the talented batsman and Travis Head, then Wade while running between the wickets.
Jonny Bairstow hurt his thumb in the morning session but was given the green light to continue keeping.