It is an important opportunity at an important stage of the season to gain a real psychological edge over Manchester United," Houllier said.
"A win will put us eight points clear of them and, yes, that would give us an important boost.
"I put Manchester United on the same level as Arsenal and Chelsea as our main rivals in the contest to win the Premiership, but we are at home and that is important, and we have a chance to take an important opportunity at this stage."