'Absolutely plumb': Pakistan centurion's big slice of luck

Pakistan batsman Babar Azam frustrated Australia after posting just the second Test century of this career despite looking "gone" on 75.

Azam's ton gave Pakistan something to smile about on day four as Australia closed in on victory in the first Test at the Gabba.

'HE’S A MOLE': How Shane Warne helped Pakistan take down Steve Smith

'STINKER': Marnus Labuschagne survives clanger to notch maiden Test ton

Frustrated by his cheap first innings dismissal, Babar knuckled down to notch his second Test hundred off 160 balls on Sunday.

A master of the shorter formats, Babar is yet to flourish in Test cricket but his innings will give the tourists a lift ahead of the second and final match of the series in Adelaide from Friday.

Arriving at 3-25, Babar had looked at ease on Saturday afternoon and he cruised past 50 in the first session of day 4 on Sunday as two more wickets fell.

He survived a tight review, initially given not out on-field, after Josh Hazlewood thought he had him lbw on 75.

On first glance, the umpire’s decision seemed to be particularly kind on Azar, with the ball looking likely to take out middle and leg stump.

“From the naked eye I thought that was absolutely plumb,” Mike Hussey said in commentary for Fox Cricket.

Even Pakistan legend Wasim Akram agreed, adding: “I thought he was gone."

Replays showed the delivery would've clipped the top of leg stump, meaning the original call stood.

Babar averages above 50 in both Twenty20 and 50-over cricket, but entered the series with a Test average of just 35.28 after 21 matches.

He made 99 against the touring Australians in the UAE last year but went one better at the Gabba on Sunday when he drove Pat Cummins superbly through cover for his 13th boundary.

The Aussies looked likely to steamroll the Pakistanis on day four after picking up the wickets of Shan Masood and Iftikhar Ahmed in the first session.

However, Azar and Mohammad Rizwan put on a superb 132-run partnership to keep the visitors' slim chances of making Australia bat again alive.

Pakistan dig in to frustrate Aussies

Azar eventually fell for 104 runs after being caught behind off Nathan Lyon’s bowling but the visitors held firm to make it to tea at 6-268 - still 72 runs behind Australia’s mammoth first innings total of 580.

Muhammad also posted his maiden Test half-century, unbeaten on 77 at the break.

He survived a chance on two when he tickled one down legside off Mitchell Starc (2-64) only for the tough opportunity to be grassed by a diving Tim Paine.

Earlier, Pat Cummins (2-61) and Josh Hazlewood (1-51) each claimed a scalp in a morning session during which Pakistan went the opening 50 minutes without loss.

Cummins had the first wicket of the day when he removed opener Shan Masood who was caught behind trying to hook for 42.

In the next over, Hazlewood caught the edge of Iftikhar Ahmed (0) and wicketkeeper Paine took a regulation catch.

David Warner and Marnus Labuschagne had previously set up Australia's commanding position with big centuries, as the hosts hit 580 in reply to Pakistan's first-innings 240.

With AAP