Here's what i think,
This is perhaps one of the best time to try and beat Man United. Their defence isn't playing as well as it should. Silvestre hasn't been his usual self and the left back position is a weak area, with the new boy Evra still adapting.
In midfield, the engine room of Alonso, Gerrard and Sissoko can dominate the likes of Oshea, Smith and Fletcher.
The main threat IMO will be Wayne Rooney and Van Nistelrooy. If Carra and Sami can keep them at bay, hold on for a clean sheet, then there will be every bit of a chance that LFC can nick in a winner at the other end. Hmmm...Maybe Gerrard or Alonso?