The Wallabies started brightly as Bernard Foley scored a try after nine minutes before following that up with a confident conversion.
Foley converted yet again in the 15th minute after Nick Phipps's try but the US responded with a penalty and conversion from Alan MacGinty either side of a Mike Petri try. That took the scoreline to 10-14 going into half time.
However, the Aussies came back into the second half much stronger as Sean McMahon scored a try in the 49th minute followed by another Foley conversion. Dean Mumm grabbed a try of his own just five minutes later as the favourites looked to secure a comfortable victory.