The George Bailey-led side's nine-wicket win over 2007 champions India Friday night must have done a world of good to their morale after topping Group B with wins over Ireland and the West Indies and they would start as favourites tomorrow.
South Africa, on the other hand, would have to regroup after they shockingly let slip the Super Eights game against Pakistan from a winning position. The Proteas virtually had the game in their bag before allowing Umar Gul to run away with the match later.
The South Africans cannot repeat such a costly mistake against Australia as that would mean exit for them and would only strengthen the "chokers" tag labelled on them in big tournaments.
Australia are the in-form side in the tournament with the top-order batsmen in roaring form and the frontline bowlers among the wickets. The main worry for South Africa would be how to stop the swashbuckling Australian openers Shane Watson and David Warner, who have become the most successful pair in the T20 Internationals, from dictating terms on their bowlers.
The duo mercilessly sent the Indian bowlers on a leatherhunt in their side's nine-wicket mauling in their first Super Eights match last night. Veteran Mike Hussey has also done his bit at one down though the marauding openers have not given him much chance to play his usual role of the 'man in crisis'.
The fast bowlers -- Pat Cummins, Mitchell Starc and Watson -- also came through against India as they produce pace and bounce on a slowish Premadasa strip though they were expensive against the West Indies in their group match.
Left-arm spinner Brad Hogg has taken two wickets from the three matches he has played so far and without being expensive and he can be handful if the pitch assist slow bowlers.
If there is any cause of worry for the Australians, it could be their middle order batsmen as they have not been tested in the tournament since they have not got the chance in the three matches so far.
South Africa should blame themselves for the heart-breaking loss against Pakistan as they allowed number nine batsman Umar Gul to hit a 17-ball 32 to take his side to victory after being reduced to 76 for seven.
Faced with a do-or-die situation South Africa would be looking up to fast bowler Dale Steyn and veteran all-rounder Jacques Kallis to come up trumps tomorrow while also hoping that the top-order, including Hashim Amla, post a big total. Amla and his opening partner Richard Levi have not done much in the two matches after remaining not out in the group match against Zimbabwe and they need to fire against Australia if they want to stay afloat in the tournament.
The Proteas have a solid batting with the likes of Kallis, J P Duminy and captain A B de Villiers coming down the order but they could score just 133 against Pakistan yesterday.
In the bowling front though, it will be interesting to see who does better tomorrow between a relatively inexperienced Australians and the South Africans who have veteran fast bowlers in the likes of Steyn, Kallis and Morkel brothers.
In the spin department, another veteran Johan Botha has not done much in the three matches he played so far, having taken just one wicket but he can come in handy at the slowish Premadasa pitch tomorrow.
Australia: George Bailey (capt), Dan Christian, Pat Cummins, Xavier Doherty, Ben Hilfenhaus, Brad Hogg, David Hussey, Michael Hussey, Glenn Maxwell, Clint McKay, Mitchell Starc, Matthew Wade, David Warner, Shane Watson, Cameron White.
South Africa: AB de Villiers (capt; wk), Hashim Amla, Farhaan Behardien, Johan Botha, Dale Steyn, Jean-Paul Duminy, Faf du Plessis, Jacques Kallis, Richard Levi, Albie Morkel, Morne Morkel, Justin Ontong, Wayne Parnell, Robin Peterson, Lonwabo Tsotsobe.
Match starts at 3.30 pm (IST).