Reina does not want to see United win the Champions League after the Red Devils having already won the Carling Cup, the Club World Cup and the Premier League this season.
Reina said: “I don’t want to see our greatest rivals winning another title.”
Liverpool have won against United twice this season.
He added: “The key was we approached both games with nerve and played a passing game from man to man. That is the way to do most damage.
“I believe Barca will play that way and I hope that they win.”