Liverpool midfielder Xabi Alonso has pinpointed compatriot Xavi as Barcelona's key player, ahead of the Champions League showdown between the two clubs.
Despite Barca fielding the likes of Ronaldinho and Samuel Eto'o, Alonso believes it is his Spain team-mate who makes the Catalans tick from the centre of midfield.
Alonso told his club's official website: "Xavi would be a good addition to any club.
"I always like playing alongside him, because he makes everything look so easy.
"Even when you're not playing, it's a pleasure to watch him on the pitch, even if it's just a training match.
"He is what I would call a mature, natural-born football player. He's the best opponent I've ever faced."