Mainz beat Stuttgart in thriller
Nicolai Mueller scored twice for the home side, opening his account in the 14th minute when he dispossessed Gotoku Sakai, skipped past Benedikt Roecker and shot inside the right post.
Vedad Ibisevic equalized two minutes later with one touch from Ibrahima Traore's cross.
Okazaki put Stuttgart back in front in the 65th, latching on to Zdenek Pospech's cross, turning inside a defender and sending the ball inside the post.
Mueller grabbed his second in the 78th after a good ball forward from Eric-Maxim Choupo-Moting, four minutes before Martin Harnik scored what proved to be a consolation.
Schalke was hosting Hamburger SV in Sunday's late game.