Guardiola enjoyed a trophy-laden four years at Camp Nou, including three La Liga titles and two UEFA Champions League triumphs.
The 42-year-old departed the Spanish champions in 2012, taking a short sabbatical before joining Bundesliga holders Bayern Munich in the close-season.
And Xavi hailed the "extraordinary project" engineered by Guardiola during his time in Spain.
"Pep made his job in Barcelona. We are so proud he was our manager," he said. "(We had) four years when we won plenty of trophies. He led an extraordinary project until he decided to leave for a gap year and nowadays he is doing a brilliant job in Bayern Munich.
"Obviously, we miss things from him, as (we do) the other managers who left the club. We have another coach, we had (Tito) Vilanova last year and Tata (Gerardo) Martino this season.
"Each person has a different way to work. Guardiola had his way, Vilanova too and Martino as well. All of them are good managers and we were lucky with Guardiola because we made history."
Meanwhile, Xavi believes team-mate Lionel Messi should collect the prestigious Ballon d'Or prize, due to be awarded in January.
He added: "If I had to vote, I would vote firstly for Messi because I think he is the best in the world.
"The second would be Franck (Ribery), the third one Cristiano (Ronaldo). Those would be my votes, even though I don't have the right to vote as the second captain of the national team."
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