Australia's nightmare summer has continued, as South Africa wrapped up the one-day series 4-1 with a comfortable 39-run triumph in front of 18,002 fans at the WACA.
South Africa, minus Makhaya Ntini, Dale Steyn and Jacques Kallis, were still too good for Australia, whose top-order crumbled in reply to the Proteas' 6-288.
Left-arm paceman Lonwabo Tsotsobe (4-50) made a dream debut, snaring the key wickets of Shaun Marsh (five) and Ricky Ponting (12) in his opening spell as Australia crashed to 4-53 in the 13th over.
It was a position the hosts never recovered from, with the late hitting of Mike Hussey (78 off 96) and Brad Haddin (63 off 50) giving Australia, who were dismissed for 249 in 49 overs, only false hope after the required run-rate ballooned to more than 10 an over.
The only negative to come out of the match for the Proteas was a leg injury to Albie Morkel.
The all-rounder was forced off late in the game when he collided heavily with teammate Vaughn van Jaarsveld while attempting to catch Haddin's skied shot.
If losing both the Test and one-day series to South Africa wasn't bad enough, Australia also surrendered their No.1 one-day ranking to the Proteas following their third one-day loss on the trot.
But Ponting's charges can regain the No.1 mantle -- and some much-needed pride -- during their five-game series against New Zealand, which kicks off in Perth on Sunday.