The pair also worked together at Barcelona before sports director Begiristain convinced Guardiola to move to City.
Guardiola said, "He is the most important person in my career, he believed in me when I was nobody.
"Without him I would not be here. I am grateful to him, he is a crazy sports director. We talk often, he is an incredible person.
"Nothing happened to my career without him. We are on the same wavelength, always."