The Merseysiders booked their place in the last four of the competition with a comprehensive 6-1 aggregate win over Porto, though the Spanish champions will be a far tougher challenge.
Barca eased past Mourinhos old club Manchester United in midweek, with Lionel Messi scoring two goals in four frantic minutes to take his tally in Europe to 10 for the season.
The Argentine is the leading scorer in the Champions League and Mourinho says Liverpool will need to build a cage to stop him from adding to is tally in two weeks time.
Messi is having a phenomenal season and now with Juventus and Cristiano Ronaldo outside this fight, he knows also that the golden ball is there waiting for him, Mourinho told Russia Today.
Messi is easy to understand, but its not easy to create a cage to control him, because he comes from the right, but then stays in the middle. Its very difficult.
When Messi has the ball, one, one, one, you are dead. Thats why I never liked the individual man-to-man against Messi. Messi is a cage. You have to create a cage.