Gracia prepares to lock horns with Pochettino when Watford host Tottenham on Sunday.
He said: "I know him from Spain because he played at Espanyol and I played against him many times for other teams.
"I know him, I know the technical staff as well. And in this moment I think he is one of the best coaches, not only in England, but also the world as well.
"I think it [Sunday's televised clash] will be a good challenge for us [as a team] and for me as well."