Australia vs South Africa, 3rd Test: Usman Khawaja century powers Aussies ahead of Proteas on day 2

Adelaide: Iron-willed Usman Khawaja batted out the entire day to tilt the third day-night Test towards Australia with a masterful century against South Africa on Friday.

At the close on the second day in Adelaide, the Australians were 307 for six in reply to the Proteas` 259 for nine declared, with Khawaja unbeaten on 138 off 285 balls and Mitchell Starc not out 16. The home side lead by 48 runs.

It was Khawaja`s fifth Test century and arguably his best as Australia seek to prevent the Proteas from an unprecedented series clean sweep after huge defeats in the opening two Tests.

Khawaja, who has performed best out of the Australian batsmen in a troubled series, led the way with his wristy shot-making to put the home side in front in the pink-ball Test.

It was the first century by an Australian in the series and the stylish left-hander has now scored 307 runs in the three Tests.

"Credit to Usman to bat an entire day against a world-class attack," said team-mate Peter Handscomb, who scored a half-century on debut batting with Khawaja.

"He was very collected, very calculated and he never looked flustered ... it was awesome to watch him from the other end."

But Khawaja`s well-crafted ton was marred by a mix-up which left skipper Steve Smith stranded as he darted off for a quick single.

Smith, who was put down by Hashim Amla on 46, was sailing along when his run out for 59 came out of the blue in a bad breakdown in communication with Khawaja.

After Smith called for a quick single off left-arm spinner Tabraiz Shamsi, Khawaja took several tentative steps before wheeling back and Smith was caught well out of his ground by Vernon Philander`s throw to wicketkeeper Quinton de Kock.

Smith put on 137 for the third wicket in his 158 minutes at the crease and his dismissal summoned Handscomb to the wicket.

Khawaja and Handscomb strengthened Australia`s grip before Kyle Abbott got one through the debutant`s defences on 54.

Handscomb looked comfortable in his 78-ball stay, hitting six fours, including three successive boundaries off Philander to reach his maiden Test half-century.

But another debutant Nic Maddinson struggled with a 12-ball duck, bowled middle stump by a Kagiso Rabada inswinger.

The South African bowlers laboured to make a breakthrough for the first time in the series as Australia`s batsmen finally put up a resistance after several humiliating batting collapses.

Skipper Faf du Plessis used a total of seven bowlers in a bid to stop the Australian momentum, before taking the second new ball.

Recalled wicketkeeper Matthew Wade lasted just six balls for four, but Starc stayed at the crease with Khawaja in the day`s final overs.

The Proteas struck twice with the wickets of English-born newcomer Matt Renshaw and David Warner inside the first hour.

Renshaw, who looked so composed in his first Test innings the previous evening, fell to a superb sprawling catch by Dean Elgar in the slips for 10 in the fourth over of the day.

Abbott enticed an edge and Elgar dived across second slip to take the catch just above the ground and send the youngster on his way.

The big-hearted paceman prised the key wicket of Warner for 11 in his eighth over, getting the Australian vice-captain to edge to Elgar for his second catch.

Abbott, the Proteas best bowler with three for 38 off 25 overs, believes the Test match is in the balance after two days.

"I think tomorrow`s first session will be key. If we can pick up the last four wickets and not have a deficit of 100 or above," Abbott said.

"I think anything under 100 we would be pretty confident in knocking off and then posting a score after that."