Australian Rugby Union chief executive John O'Neill has called on the Wallabies to start living up to their reputation.
Coach Eddie Jones has brought in Lote Tuqiri for Joe Roff on the left wing and Stirling Mortlock for Matt Burke at centre in attack-minded changes for the quarter-final against Scotland in Brisbane on Saturday.
"If this team's got the ability to win the World Cup we're going to find out very soon," said O'Neill. "At this level you can't make excuses for dropped balls, unforced errors.
"This is a professional game, players are highly paid, they're trained as well as we can possibly provide for them."
O'Neill believes the inclusion of Roff and Tuqiri is a crucial step towards Australia retaining the World Cup.
"The selectors had to think long and hard about Joe Roff, a great player, a huge contributor to Australian rugby - it was a very difficult decision.
"Tuqiri is absolutely raring to go. From my observations from afar he's been destined to get into the run-on team and Stirling Mortlock, if he's back to his best, is a game-breaker."
After surviving a major scare in the 17-16 victory over Ireland, the simple fact as far as O'Neill is concerned is that it is time for the Wallabies to show they are in the mood to defend the crown they won four years ago.
"It's time to actually put it together," he said. "Their preparation, training and fitness levels are fantastic. Their execution let them down on Saturday night (against Ireland) and other things like their lineout and scrum let them down."
Jones has also made an important change on the bench, where Justin Harrison has been preferred to Daniel Vickerman.
Harrison's lineout prowess is impressive, and that could be a valuable asset against the highly-rated Scottish unit.
Australia lost five of their lineout throws in the win over Ireland, and Jones is anxious to avoid a repeat against Scotland.
Meanwhile, Tana Umaga has failed in his bid to overcome a knee injury in time for New Zealand's quarter-final against South Africa in Melbourne on Saturday, and Leon MacDonald will continue to occupy the number 13 jersey in his absence.
MacDonald, primarily a full back, has shown his versatility and strength by filling in at centre. He will also bear the responsibility of goal-kicking against the Springboks.
Jerry Collins and Chris Jack have overcome knocks to secure their places in the starting line-up. Collins was replaced by Marty Holah in the win over Wales because of a rib cartilage injury, but coach John Mitchell was confident the Wellington number eight would continue his rapid progress from the problem.
Jack comes back into the side at the expense of Brad Thorn after missing the clash with Wales because of an ankle injury.
AUSTRALIA (v Scotland): M Rogers; W Sailor, S Mortlock, E Flatley, L Tuqiri; S Larkham, G Gregan; B Young, B Cannon, B Darwin, D Giffin, N Sharpe, G Smith, P Waugh, D Lyons. Replacements: J Paul, A Baxter, J Harrison, M Cockbain, C Whitaker, M Giteau, J Roff.
NEW ZEALAND (v South Africa): M Muliaina; D Howlett, L MacDonald, A Mauger, J Rokocoko; C Spencer, J Marshall; D Hewett, K Mealamu, G Somerville, C Jack, A Williams, R Thorne , R McCaw, J Collins. Replacements: M Hammett, K Meeuws, Brad Thorn, M Holah, S Devine, D Carter, C Ralph.