Mitchell Johnson went from intimidatory to outright unplayable in a fiery opening spell that destroyed South Africa’s top order on Thursday.

Johnson made captain Graeme Smith look like a tailender before the Proteas went to tea on day two of the opening Test in Centurion at 4-63, well behind Australia’s first innings of 397.

AB de Villiers batted smartly for the final hour of the second session and even managed to hoike Johnson for a six when the left-armer returned for his second spell.

But the hosts face an enormous task to rebuild after Johnson’s carnage, while Australia would need to play incredibly poorly to lose from this position.

It took almost five hours for centurions Shaun Marsh and Steve Smith to give the visitors the advantage, but Johnson needed only 3.1 overs to make it a vice-like grip.

It would be unfair to suggest the left-armer continued his form of the Ashes, where he claimed 37 English scalps to be man of the series.

This was better.

On a bouncy pitch where his slinging action had the ball travelling up to 150km/h, Johnson was at his brutal best.

First in the firing line was Smith, who had looked so comfortable while taking 10 runs from the opening over bowled by Ryan Harris.

He lasted two deliveries against Johnson, one thudding into his thigh pad and the other clattering into his bat handle when it reared violently toward his skull.

Marsh ran around from first slip to complete a difficult catch.

Alviro Petersen was next to go when a tame attempted cut shot gave wicketkeeper Brad Haddin a regulation edge to pouch.

Faf du Plessis, batting at No.4 in place of retired legend Jacques Kallis, jutted his bat forward to another rising Johnson delivery that caught the edge and flew to Michael Clarke at second slip.

Peter Siddle then trapped Hashim Amla lbw for 17 after Clarke successfully reviewed the original not out decision.

De Villiers was 25 not out with JP Duminy on five.