Australia tried to redeem all of the questions raised about their form in last two ODIs in a single one. Even though they have already lost the series, they made a statement that they are not to be taken lightly.
It's a dead rubber match which is why this isn't much of a statement to be honest. South Africa were even missing some of their key bowlers like Rabada and Ngidi. Frankly, the opposite happened.
The Proteas decimated the Aussies on their own turf in a one sided manner which is why they proved why they should be feared across all formats at the moment. The legendary chokers aren't choking anymore.