Messi has enjoyed yet another impressive campaign in front of goal, finding the net 26 times in all competitions to keep Barca on course for a domestic and European treble.
"You know, they have a guy who is not from this world," he told Marca. "He's different, a 'superclass'. But this is not about one player, it is about the whole team.
"It's a beautiful match. This season we are not the same as last season, of course, and they are very good but in the end it is a cup tie and you never know what happens. That's why we love football. I'm pretty sure we can beat them if we play together. We'll see."
Chelsea play host to Barcelona on February 20, before travelling to Camp Nou for the reverse fixture three weeks later.