Oz bat through Day 3 to lead by 402 runs

Steve Smith's failure did nothing to slow Australia's march toward expected victory in the first test against South Africa as the tourists batted through the entire third day on Saturday to build an imposing lead of 402 runs.

Smith was out for 38 lbw to part-time spin bowler Dean Elgar, the first time in six test innings that the Australia captain hasn't passed 50.

But 53 from opener Cameron Bancroft, and contributions from Smith, David Warner (28) and Shaun Marsh (33) ensured Australia moved on to 213-9 at stumps, having opened its second innings at the start of the day.

With a lead of 189 from the first innings, Australia was in complete command despite the three wickets each for spinner Keshav Maharaja and quick bowler Morne Morkel and two for pacer Kagiso Rabada to go with Elgar's surprise strike.

Elgar, who had bowled a total of six overs in tests in the last two years, got the No. 1-ranked test batsman with the fourth ball he delivered. It straightened enough and hit Smith on the pad in front as he tried to sweep. Smith tried, also, to survive through a decision review and failed.

Australia did lose Warner and Usman Khawaja (6) reasonably early at Kingsmead but that didn't affect the tourists' rapid run rate before lunch - they were going at over four an over in the first session - as they built a dominant position in the series opener.

Bancroft's half-century ended a run of poor form when he went seven innings without a 50. He got to his half-century with a hook for four off Morkel, one of 10 fours for him before he came down the track to spinner Maharaj and was stumped just a few minutes before the lunch break.

Bancroft and Warner put together a 56-run opening stand, playing with positive intent before Warner played a mistimed pull to substitute fielder Wiaan Mulder off Rabada. Maharaj had Khawaja caught off the glove for the first of his three wickets.

After Smith went, Mitchell Marsh fell to Rabada via Hashim Amla's 100th catch in test cricket. Tim Paine was out to Maharaj and Morkel collected his three in the final session.

Smith's 38-run stand with Shaun Marsh was the next-best after the half-century the openers put on, but Australia was still dictating the pace of the game by the time bad light stopped play.