Australia opener Usman Khawaja continued his run-scoring spree against Pakistan and completed his second hundred of the series as the touring side took firm control of the deciding third and final test against Pakistan in Lahore on Thursday.

The Pakistan-born Khawaja, who top-scored for Australia in the first innings with 91, was unbeaten on 100 at tea with Australia reaching 202-2 in their second innings at tea on the fourth day, stretching their overall lead to 325.

The 35-year-old left-hander scampered for two runs in the final over before tea to complete his 12th hundred in tests. He scored 97 in the opening test at Rawalpindi and 160 and 44 not out in the second at Karachi.

Former captain Steve Smith was 12 not out at the break, becoming the fastest to reach 8,000 runs in tests during his knock at the Gaddafi Stadium.

Khawaja added 96 for the opening stand with David Warner, who hit six fours and a six in his knock before being dismissed shortly before lunch for 51, cleaned up by fast bowler Shaheen Shah Afridi.

Khawaja, who returned to the test side in January after two years during the home Ashes series against England, was bowled on 31 by pacer Naseem Shah but was reprieved when the television umpire ruled the bowler had overstepped the crease.

Marnus Labuschagne, who made 36, was the only other wicket to fall for Australia after he added 65 for the second wicket with Khawaja.

With some deliveries keeping low after pitching, Australia are expected to declare their second innings in the final session on Thursday to give their bowlers an opportunity to have a crack at their opponents for a series-clinching win.

The first two tests -- the first between the sides in Pakistan since 1998 -- were drawn.