Australia's Mitchell Starc (C) reacts after a delivery as noin-striking batsman South Africa's Quinton de Kock looks on. Photograph:( AFP )
The Australians will play third placed England in next week's semi-finals
South Africa beat Australia by 10 runs to stop the holders finishing the World Cup group stage on top of the table.
Faf Du Plessis' side made 325-6 and restricted Australia to 315 all out in the run chase on Saturday.
Australia's defeat -- only their second of the tournament -- meant they had to settle for second place in the group table, which concluded with their match at Old Trafford.
The Australians will play third placed England in next week's semi-finals, while table-toppers India face fourth placed New Zealand in the other last four clash.