Aus lay waste to Proteas top order

Australia ripped through the South African top order to leave the tourists in damage limitation mode on 78 for four at lunch on the opening day of the first Test on Thursday.

Laying to rest concerns about the fitness of two thirds of their pace attack and the WACA wicket, the hosts sent back Stephen Cook, Dean Elgar, Hashim Amla and JP Duminy inside the first hour at the cost of just 32 runs.

Proteas skipper Faf du Plessis, who won the toss and elected to bat, was 37 not out at the break, having steadied the ship with a 46-run partnership with Temba Bavuma, who was unbeaten on 17.

Mitchell Starc, who had tested his recovery in just one Sheffield Shield outing since suffering a nasty gash on his leg in September, wasted no time in proving his fitness.

Clocking 147 kph and getting plenty of bounce from the opening delivery of the day, the left-arm paceman took just four balls to induce Cook into an outside edge that Mitchell Marsh soared to snatch out of the air at gully.

Three overs later and Josh Hazlewood, who was rested from Australia's 5-0 one-day international humiliation in South Africa, struck to take the key wicket of Hashim Amla, again before the batsman had got a run on the board.

Amla also got an outside edge with a prod forward but this time there was no difficulty to the catch, skipper Steve Smith taking it comfortably at second slip.

That reduced the tourists to 5-2 and it could have been worse had Usman Khawaja held on to a difficult low catch at forward square leg to dismiss Elgar off Starc.

Elgar did not last long after his reprieve, however, and had scored only 12 runs when Hazlewood claimed his second victim with a superb delivery that took a nick on the way back to wicketkeeper Peter Nevill.

Seamer Peter Siddle, also on the comeback trail after a back injury, replaced Starc and almost had an immediate impact, Nathan Lyon at full stretch getting fingers to a Duminy shot at point but failing to hold on.

Duminy had 11 runs on the board when Siddle finally got his man with umpire Nigel Llong adjudging the batsman had a nick on the ball as it went through to Nevill and the DRS not producing sufficient evidence to overturn the verdict.

South Africa decided against going with a four-prong pace attack and handed a debut to left-arm spinner Keshav Maharaj.