Australia crushed Russia 68-22 to secure their place in the Rugby World Cup quarter finals on Saturday but suffered another injury blow when winger Drew Mitchell pulled a hamstring as they lost their way in the second half.
The Wallabies join New Zealand and South Africa in the last eight and they might have to beat both their Tri-Nations rivals to reach the final if Ireland beat Italy on Sunday to finish top of Pool C.
Australia's bonus-point victory was always going to be a formality but they still showed a sharpness, particularly in the backs, as seven tries, including two for dynamic flanker David Pocock, had them 47-5 ahead at the break.
They were less fluent as the rain fell in the second half and lost Mitchell, who suffered a broken leg in April, when he pulled up when heading for what would have been his third try.
Coach Robbie Deans said later that the injury "looks a bad one" for the winger, and "it looks like it will end his tournament."
James O'Connor converted nine of their 10 tries.
"Overall, we're happy to get the win but at the back end there things didn't really go the way we wanted," Australia captain James Horwill told reporters.
"We did what we needed to do and now we move on and just wait to see who we play next week."
Russia, who could barely make a tackle in the first 40 minutes, were a different side after the break and ended the day with three tries by Vladamir Ostroushko, Denis Simplikevich and Konstantin Rachkova.
"It was amazing, we didn't get the best of starts and we struggled to keep our composure initially," Russia fullback Vasily Artemyev said.
"We put a few things right and I think we deserved our tries."
Scorers
Australia Tries: David Pocock (2), Drew Mitchell (2), Berrick Barnes (2), Stephen Moore, Adam Ashley-Cooper, Ben McCalman, Salesi Ma'afu. Conversions: James O'Connor (9).
Russia Tries: Vladamir Ostroushko, Denis Simplikevic, Konstantin Rachkov. Conversions: Rachkov (2). Drop goal: Rachkov.
Referee: Bryce Lawrence (New Zealand).
