Lancaster refused to look for scapegoats after the dramatic loss to Wales and continued to back his captain Chris Robshaw, despite the flanker's decision not to go for a late equalising penalty and kick to the corner instead, which ultimately helped Wales win the match.
"I'm not going to hang anyone out to dry," he said despite a crescendo of criticism led by former England coach Sir Clive Woodward.
England flanker Tom Wood was one player who admitted to regret over the way the host nation team had played and the decision not to take the late penalty attempt.
"In hindsight it's a regret but at the time it was a decision we bought into," said Wood.
"We thought we were going to be brave and nail it. Had it been 10 or 15 metres further infield we would certainly have gone for the points. The fact it was on the touchline was the deciding factor. We didn't feel it was the percentage shot at goal.
"We backed ourselves as a forward pack to take them on and they stood firm. Fair play to them. For much of the game it didn't feel like we were going to lose. We just kept letting them back into the fight with ill-discipline and penalties."
Another loose forward James Haskell agreed England could not slip against Australia.
"It's going to be like a final for us. Everyone involved will have to imagine it's the last time you put that white shirt on. We have to leave it all out there. We can't afford to do what we did this weekend. We can't get ahead and then shoot ourselves in the foot.
People are going to be harsh and it's going to be pretty cut-throat in the next few days."
Adding to his problems, Lancaster has injury worries leading into the game. Forwards Courtney Lawes and Billy Vunipola are both almost certain to miss out with knee injuries and Jonathan Joseph is not expected to recover either. England, however, are hopeful that Ben Youngs and Ben Morgan will respond to treatment and be available for selection.