Call me naive, but, with run chases like this, at the fall of Khawaja's wicket, I would have sent in a Siddle with instructions to throw the bat around like a mad man and instruct Davey Warner to do the same.
2 for 168 could be turned into 4 for 220 or 230 in a hurry and you have essentially broken the back of the chase.
Instead, by allowing England to bowl to timid batsmen looking to knock the ball around, Australia is has handed the initiative back to england and will lose this test comfortably after being in the box seat for most of the afternoon.
FFS, they had their throat on the English bowlers throat, then with the loss of Khawaja's wicket, they went into their shells and surrendered any advantage they had.
Pitiful.