"There have been some great teams in history, Pele's Brazil, (Johan) Cruyff's Ajax, (Arrigo) Sacchi's Milan but in the past 20 years this Barcelona team is the best," he told Bild.
On Messi, he added: "He is the best player of all time - better than Pele, Maradona or Cruyff. We have to protect him as he is crucial.
"Without him we would not be what we are."
Barcelona has swept away every team that have come up against this season, including the dismantling of Manchester United in the Champions League final.
Xavi, though, was critical of the approach adopted by Jose Mourinho's men throughout the season.
He said: "Madrid were the hardest opponents but not because they played football but because they wanted to destroy the game.
"I like Manchester United's approach a thousand times better. It would be interesting to see what would happen if Real did play."
Speculation prior to the Wembley showpiece suggested coach Pep Guardiola was on the verge of standing down but Xavi hopes the former Barcelona midfielder "stays forever".
He added: "He (Guardiola) is very intelligent, very enthusiastic and very 'Barcelona-ish'.
"He is a great coach and I hope he stays forever, if not as coach then as sporting director or president."
