Peter Siddle scored his maiden first-class hundred and then the Australia A bowlers proved too much for Scotland who crumbled to 149. James Pattinson, one of a trio of likely Ashes bowlers in operation, claimed three wickets before the Australians opted for batting practice rather than a swift victory.
Siddle, whose previous best was 87, had resumed on 85 and, as the Australians pressed for a declaration, he was given a life on 93 but a sparkling cover drive brought him his hundred.
Scotland started their reply full of nerves with Josh Davey facing 15 deliveries before being caught behind for a duck. Matt Machan showed promise from the other end hitting a couple of fours off the bowling off Chad Sayers, but Freddie Coleman was run out by a superb direct hit from Nathan Lyon, and Richie Berrington soon followed, being clean bowled for 1 by Pattinson.
Lyon, who could come under pressure for his Test berth if Fawad Ahmed is fast-tracked into the main squad, was given an early bowl and beat Machan in the flight. Moneeb Iqbal lost his off stump when he shouldered arms at Pattinson and Matthew Cross, the wicketkeeper, fell to Moises Henriques when he left his bat in the air while avoiding a bouncer. When Ashton Agar claimed two wickets Scotland were in tatters at 83 for 9.
However, Callum MacLeod and Iain Wardlaw added a record 66 for the last wicket as they attacked the spinners, especially Lyon, although the offspinner finally ended their fun when MacLeod picked out deep square-leg the ball after reaching fifty.
Australia opted not to force the follow-on to allow their top order, which had not been fluent in the first innings, another chance. Jordan Silk and Usman Khawaja edged to first slip but the lead swelled to nearly 400 by the close.