Fourth one-day international, Melbourne:
Australia 268-7 (49 overs) beat South Africa 267-8 (50 overs) by three wickets
Steve Smith scored 104 off 112 balls as Australia beat South Africa by three wickets to take an unassailable 3-1 lead in the five-match one-day series.
Smith shared a sixth-wicket stand of 121 with wicketkeeper Matthew Wade as the hosts chased 268 in Melbourne.
Australia had slumped to 98-5 before Wade and Smith guided them to 219-6, and James Faulkner's unbeaten 34 helped secure victory with an over to spare.
Captain AB de Villiers top scored with 91 in South Africa's total of 267-8.
The fifth and final one-day international - which is the last match of South Africa's tour - takes place at Sydney on Sunday.
Australia then begin a four-Test series against India on 4 December - with skipper Michael Clarke battling to be fit for the first Test in Brisbane because of a hamstring injury which has kept him out since the first one-dayer against the Proteas