Former Hampshire star Simon Katich took three wickets as Australia won the second Test match against South Africa by 175 runs - and seal an unassailable 2-0 lead in the three-match series.

South Africa began the final day in Durban with hope of gaining a draw but never looked liked doing so after losing the key wicket of Jacques Kallis (93) early in the first session.

Only Mark Boucher put up any resistance for the hosts with a gritty 107-ball 25 - before he handed slow left armer Marcus North, Hampshire's latest signing, a return catch.

The tourists reduced the Proteas to 370-9 - Graeme Smith did not bat due to a broken finger - with Katich claiming 3-45 to help his side retain their world number one ranking with the final Test in Cape Town still to come.

Resuming the final day on 244 for two, Kallis was soon dropped for the second time in the innings, this time by Michael Clarke after also being let off the hook by Marcus North when on 0 yesterday.

This time the missed chance was not so costly, however, as Kallis fell in the next over trying to fend off a Mitchell Johnson delivery that he edged to Ricky Ponting at second slip.

Kallis' demise just seven short of a ton broke a fighting 187-run partnership with AB de Villiers, and with it seemed to signal the end of the hosts' resistance.

De Villiers followed a short time later for 84 when he received an almost unplayable delivery from Peter Siddle that he deflected to wicketkeeper Brad Haddin.

Haddin then dropped JP Duminy off the same bowler when the ball slipped through his gloves with the batsman on six.

But he made amends when a Ben Hilfenhaus bouncer gave Duminy (17) no chance of getting his gloves out of the way.

With lunch on the horizon, Ponting threw the ball to Katich who struck with his second delivery when a thick edge from Paul Harris (5) was snapped up by Siddle running back from mid-on.

Boucher and Morne Morkel dug in after lunch, the pair batting for over an hour before the former tried to turn North onto the leg side only to send a leading edge back to the bowler.

Morkel followed a short time later when he edged onto his pads and Haddin managed to trap the ball between his legs to send the batsman back to the pavilion for 24.

Dale Steyn was last man to fall, stumped as he attempted to swing Katich across the line.

Katich, who bowls left arm chinaman, was the pick of the Australian attack, while Siddle claimed 3-61.