Pakistan coach Mickey Arthur said after day one that they would aim to score at least 280 in their first innings.
Conversely, Australian paceman Jackson Bird noted that an early wicket or two in the first hour on day two would tilt the Test strongly in their favour.
So the 107-run stand so far between Azhar and Asad shapes as pivotal in this Test.
Azhar needed plenty of patience and nerve to bring up his first MCG Test century.
He had faced 233 balls and hit only eight boundaries, bringing up the ton with a leg-glance off part-time spinner Nic Maddinson for two.
It was the first century for Pakistan at the MCG since Mohammad Yousuf's 111 in the 2004 Boxing Day Test.
He faced 95 balls on Monday before hitting his first boundary.
After the rain delay in his 90s, Azhar also had to contend with a few seconds of horror thanks to a scoreboard error.
Bowler Jackson Bird deflected a straight drive from Asad onto the stumps at the non-striker's end and the umpire called for a routine review.
Azhar clearly was in his crease, but the scoreboard briefly flashed "out" before it was corrected.
Australian captain Steve Smith then brought on himself and Maddinson with their part-time spin, trying to buy a wicket.
But Azhar had no trouble bringing up his century.
- AAP