The Barcelona midfielder says the controversial coach gave his side extra motivation but stressed that they will still fight just as hard for titles
The Portuguese is set to step down once the Liga campaign concludes, ending his three-year spell in the Spanish capital, but the Barca captain believes los Blancos will be just as good without him.
"Madrid will remain competitive with or without Mourinho," Xavi told Marca.
"With Mourinho, we have still won trophies. During the three years that he has been here, he has taken the odd title from us, but we have continued to win. That must remain our goal.
"Mourinho is a controversial coach who has always given motivation to Cules, but what is clear that La Liga has lost an important coach in world football.
"He served as extra motivation."
Barca are currently chasing a 100-point tally in La Liga and Xavi is hoping his side can seal a place in history.
"Our motivation is to get the record of 100 points."
Barcelona face a local derby with Espanyol on Sunday.