Mourinho is one of only three coaches, along with Ernst Happel and Ottmar Hitzfeld, to have won the Champions League with two different clubs and could stand out on his own if he leads Real Madrid to their tenth European crown.
Xavi, though, believes Mourinho's pragmatic approach to management means he will not be ranked in the same category as Pep Guardiola for future generations.
"Mourinho will not go down in football history," he told Reserved Area on Canal+. "For me, Guardiola is the best and has been the best during the four years he spent in charge.
"He has revolutionised football. Chelsea won the Champions League this year and yet Barca remain the benchmark for world football."
Xavi also said that Lionel Messi would be the only deserving recipient of this year's FIFA Ballon d'Or.
There have been suggestions that Cristiano Ronaldo, having helped Madrid to La Liga, could take the crown if he excels at Euro 2012 but Xavi said of Messi: "He's the best player I've seen in my life.
"It would be an injustice if any other player won the Ballon d'Or, because no other player is at his level. Messi has helped me to become a better player."