Mourinho was critical of United's fans after their 2-0 victory over Hull City in the EFL Cup on Tuesday night, and the Portuguese has said that they must match the effort which Liverpool's supporters produced when the teams met at Anfield in October.
The 53-year-old told reporters: "Now is just a question of having a little bit extra in a match which for them means a little bit more.
"It's for them that the match means something more. They have to make us feel that feeling we felt that at Anfield – we felt clearly for the Liverpool fans it was more than a match.
"Now we play at home we have a huge percentage of our fans compared with Liverpool fans."
United head into the match just five points adrift of second-placed Liverpool in the Premier League table.