I think Australia must qualify for underdog status since they have been outplayed for most of the series, only able to hang on through pure bloodymindedness, but having said that, I have grown accustomed to seeing them come back from the brink of disaster and take the win.
I can't help thinking that they will do it again, but I also have this nagging feeling that perhaps the time has come for England to return.

The short answer: Dunno