DAY FOUR

For the fourth straight time, Australia starts the day batting; this time looking for some rapid runs.

Usman Khawaja and Marnus Labuschagne are out there going at just about a run a ball (61 off 70), with Australia 1-81, leading by a whopping 489.

I think they'll try to slap an extra 50 or so before captain Pat Cummins declares for the second time in this Test (and fourth time in his brief Test captaincy career), putting Pakistan in to try to bat out the best part of two days on a crumbling Karachi deck.

Then the Aussies will try to get the ball reverse-swinging the same way they did yesterday (anyone else still feel sick talking about Australia getting the ball to reverse?), or get some big wickets out of Nathan Lyon and Mitch Swepson, and skittle Pakistan for something resembling their first-innings 148.

A lot of action still to come today, and I can't wait to bring it to you. This series really came to life yesterday.