South Africa capitulated Thursday against rampant top-ranked Australia to lose the second Test in Melbourne by an innings and 182 runs On Thursday and with it the series.

It capped a dismal first two Tests for the Proteas who slumped by six wickets in the opener at Brisbane inside two days, with a potential face-saving third match at Sydney still to play.

They resumed day four on 15-1 after skipper Dean Elgar was caught by Alex Carey off Pat Cummins for a duck before rain halted play early on Wednesday.

But their resistance didn't last long with three wickets falling before lunch at the Melbourne Cricket Ground and the rest in the second session as they meekly succumbed for 204.

Temba Bavuma top-scored with 65 while Nathan Lyon took 3-58 in a depleted, injury-hit, attack.

It leaves South Africa facing a trip to Sydney next week for the final Test with only pride to play for and potentially some changes to a batting line up that has largely failed to fire.

Australia will have a new-look team with Cameron Green and Mitchell Starc already ruled out as they race the clock to be ready for a blockbuster series in India in February.

Josh Hazlewood is set to return in Sydney after recovering from a side strain, declaring Thursday he was fit after missing the last two Tests, with Green's replacement to be decided.

Theunis de Bruyn (28), Sarel Erwee (21) and Khaya Zondo (one) all departed before lunch at the hands of Australia's high-class pace attack.

Then the spin of Nathan Lyon, and two careless run outs, ended any hope they had in the second session.

- Bruised finger -

Australia declared on Wednesday at 575-8 built on the back of man-of-the-match David Warner's 200 in reply to South Africa's first innings 189 and then took control with the ball.

The wickets fell despite the hosts' attack being depleted, with Cameron Green, who took 5-27 in their first innings, ruled out of bowling again in Melbourne -- and the final Test in Sydney -- with a fractured finger.

Mitchell Starc was also nursing a bruised and bloodied finger, but he played through the pain and his sheer pace caused plenty of problems.

Erwee, who resumed on seven, hit a superb drive for four off him as his confidence grew, but Starc quickly got his revenge, trapping him lbw with a cracking yorker.

De Bruyn, who was dropped late Wednesday, began on six and built up to 28, but he soon followed his teammate back to the pavilion.

This time Scott Boland did the damage, enticing an edge that was taken by the ever-reliable Smith in the slips for his 150th catch. He is 14th on the all-time list, led by Indian great Rahul Dravid's 210.

South Africa were under the pump and needed to dig in, but Bavuma inexplicably attempted a single from Cummins and Khaya Zondo was easily run out by a Travis Head underarm throw.

It left them teetering at 65-4 before Bavuma and Kyle Verreynne knuckled down.

But Boland struck again soon after lunch with Verreynne, one of their best batsmen this series, out lbw for 33.

Lyon's spin removed Marco Jansen before another disastrous run out involving Bavuma, with Keshav Maharaj out after a confusing mix-up as they went for a third run and Starc made a direct hit.

More weak dismissals by Lyon and a rare wicket for Steve Smith ended the match.