Ryan Harris took two wickets in three balls with just under five overs left of the third Test to dramatically win Australia the series against number-one ranked side South Africa in Cape Town.

Hosts South Africa went into the final session with three wickets remaining but little batting below the duo of JP Duminy and Vurnon Philander.

Duminy got to 43 before cheaply giving away his wicket by flicking Mitchell Johnson's delivery down the leg side straight to Nathan Lyon at leg slip.

That brought Dale Steyn to the crease and although the Australian bowlers attempted to rough him up, the fast bowler stuck around with some dogged defensive strokes.

The tourists thought that they had got key man Philander for 45 when Johnson's vicious bouncer popped up off his shoulder and was caught. Umpire Aleem Dar agreed that the ball had flicked Philander's glove on the way through and signalled out.

Philander reviewed the decision and even though video evidence suggested that the ball had clipped his thumb, his hand was off the bat so he couldn't be given out to the annoyance of the Aussies.

They didn't seem to be going anywhere but then Harris struck with the first ball of a new spell, curling a yorker past Steyn's defence and against off-stump.

Morne Morkel was the last man up and he lasted just two balls as Harris also took out his stumps to spark wild Australian celebrations, with Philander finishing on 51 not out down the other end.

Harris and Johnson were the top wicket-takers in the match with seven dismissals apiece.

Australia win the series 2-1 thanks to today's 245-run victory and the 281-run triumph at Centurion in the first Test.