The Australians completed a truly professional victory by 36 runs over South Africa at the Warner Park in St Kitt's, as the Tri-Nations series changed location.
Despite star batsman David Warner suffering a broken finger while batting in making 109, the Aussies dug deep to overcome a solid display.
The world champions eventually triggered a huge collapse as the Proteas crashed to 252 all out.
It was later announced that Warner has been effectively ruled out out of the triangular series and may require surgery for a broken left index finger suffered while fielding during Australia’s over South Africa in St Kitts on Saturday.
In a grievous blow to Steven Smith's side, Warner will be lost to the top order for the remainder of the tournament and is now in a race to be fully fit in time for the start of the Test tour to Sri Lanka in July. He had made an unbeaten half-century and a century in three innings of the triangular series so far, following a successful IPL.
Australia's team doctor Geoffrey Verrall said Warner's recovery time could be anywhere between two and six weeks if he does not require surgery, but he may be out for longer should a procedure be required.
"The X-Ray showed an intra-articular fracture of the distal phalanx of the index finger of the left hand - the top part of that finger," Verrall said. "We will assess the situation over the coming days to see if the injury requires a surgical option but should that not be the case then David is likely to be available to return to play in somewhere between two and six weeks."
The selector on duty Trevor Hohns and interim coach Justin Langer are yet to decide whether Warner will be replaced by another player flown in from Australia or elsewhere. Warner said the injury would provide him with an opportunity for downtime ahead of a demanding international schedule over the next 12 months.