Fair play to Shaun Marsh. Came into this match under pressure - possibly more so than any of the other fringe players in either side, given the number of chances he has failed to take already in his test career - and had to deal with his side having lost early wickets, and only a little bit of Paine and Starc to come. That Steve Smith has made runs should come as no surprise, but Marsh doing likewise is a huge tick for the Aussies.
And given Glen Maxwell's 213* - and his own brother's 141 - elsewhere in Australia at the same time, Marsh's knock isn't just vital for this test, but also his place in the remaining tests.
My gut is that Oz will roughly be bowled out for our score, leaving it as a one-innings shoot-out.