Hyypia is now joint-manager at Bayer Leverkusen.
He explained: "I haven't had a lot of managers and coaches in my career but from every one I tried to take the positive things. The negative things, I don't want to bring them into my coaching.
"If we are talking about football tactically, maybe I learned the most from Benitez. Tactically he was good and maybe I'd say I've learned the most from him."