|| AFP ||

Usman Khawaja and Steve Smith dug in to stretch Australia's lead and take the first Test away from Pakistan Saturday, as veteran spinner Nathan Lyon moved within one wicket of the 500-mark.

The hosts reached stumps on day three in Perth at 84-2, building their lead to 300 after bowling out the visitors on the cusp of tea for 271 in reply to their first innings 487.

Veteran spinner Lyon was the best of the bowlers with 3-66, but he was made to wait to reach a milestone that will put him in elite company alongside just seven other players.

At the close, Khawaja was on 34 and Smith 43 as Pakistan's hopes of a first Test win in Australia since 1995 faded.

The home side had a shaky start with first innings century-maker David Warner out for a duck.

The 37-year-old, fresh from his defiant 164, mis-timed a pull shot from Khurram Shahzad and lobbed to Imam-ul-Haq for a comfortable catch at mid-wicket.

Marnus Labuschagne also surrendered cheaply on a pitch offering uneven bounce, out for two with Shahzad again the tormentor, tempting a big edge taken by wicketkeeper Sarfaraz Ahmed.

It left Australia tottering at 2-5. 

But Khawaja and Smith steadied the ship with an unbeaten 79-run partnership heading into day four and a potential declaration.

Chipping away 

Pakistan resumed on 132-2 after building a solid foundation in the run chase, but they were no match for Australia's top-class attack. 

Stoic opener Haq began on 38 and nightwatchman Shahzad on seven.

Shahzad, on his debut, lasted just two balls before Pat Cummins took out his middle stump in the first over with a full and straight delivery.

That brought dangerman Babar Azam to the crease in his 50th Test, tentatively facing 13 balls before getting off the mark with a cover drive to the ropes off Cummins.

Biding his time against a seam attack finding bounce and speed on a pitch baked by the sun, he struck another in Cummins' next over to ensure the scoreboard ticked over.

At the other end, Haq continued chipping away and brought up a ninth Test 50, and his first in Australia, off a glacial 161 balls with a single off Lyon.

But the runs were hard to come by and when Mitchell Marsh was introduced, he immediately made an impact, removing Azam for 21, with the former captain edging to wicketkeeper Alex Carey.

It sparked a mini-collapse, with Haq stumped for 62 when Lyon was brought back into the attack, charging down the wicket in a lapse of concentration, with Carey whipping off the bails.

Sarfaraz Ahmed lasted just six balls, having no answer to Mitchell Starc's swinging delivery that sent the stumps flying.

Australia took the new ball after lunch and Josh Hazlewood produced a quality bouncer that Saud Shakeel tried to fend off but lobbed to Warner at slip.

He departed for 28 and Faheem Ashraf followed for nine, caught low by Khawaja at square leg off Cummins.

Lyon returned to take his 499th wicket, with another stumping from Carey accounting for Aamer Jamal, before Travis Head's part-time spin took care of Shaheen Shah Afridi.