Louis van Gaal has admitted that his side face a "big challenge" and issued a rallying cry to the fans as United attempt to overturn a significant Europa League deficit on Thursday.
First leg goals from Daniel Sturridge (a penalty) and Roberto Firmino have left the Reds with a mountain to climb at Old Trafford.
After the 2-0 defeat at Anfield last week, United must win by at least three clear goals to progress to the quarter-finals.
A 2-0 win would send the tie into extra-time with the possibility of penalties looming large, though a single Liverpool away goal would leave United needing four in reply to progress.
Despite that prospect, Van Gaal refused to give up hope and said that his side are 'thinking only of scoring'
"It is much more important that we beat Liverpool tomorrow and that is our aim.
"When we can do that with two goals difference and without conceding, then we have extra-time and, with our fans, we can make it.
"It is always a big challenge when you are behind, but the atmosphere at Anfield had a big impact and I hope it shall be the same for us also- we don't fulfill the expectations and still the fans of Manchester United support this team so that is fantastic
"We have to believe and we are not thinking about conceding, but if we do it is possible to score four as we have done in the last round against Midtjylland."
Luke Shaw, Wayne Rooney, Phil Jones and Will Keane remain long term absentees for United, Ashley Young, Cameron Borthwick-Jackson and Antonio Valencia are not ready to return whilst Bastian Schweinsteiger is still not fit enough to start.
Jesse Lingard missed the first leg through suspension but is available for this one and looks likely to feature.
Jurgen Klopp (who steps out for the first time at Old Trafford as a manager) and his in-form side topped their group in this season's Europa League and reached this stage with a narrow aggregate win over Augsburg in the last round.
"2-0 was an almost perfect result, we would liked to have won more clearly but there is nothing to criticise
"We are in a good position and want to go to the next round but the job is not finished yet" said the German.
Form guide: United W W W L L D Liverpool D W D W W W
Match odds: United 34/5 Draw 8/4 Liverpool 12/4 United to win 3-0 33/1
Referee: Serbian Milorad Mazic (voted the World Cup's worst)