Buttner was impressive at left-back in the 1-0 win.
"This team, if you ask me, is just full of winners," Van Persie said. "Everyone knows what he has to do. I was never in doubt, even if it was still a small score at 1-0.
"I was always confident we would win this game because of players like Mike (Carrick), Vida (Nemanja Vidic), Chris (Smalling) has been playing really well, Alex (Büttner) just comes in and plays well... everyone knows what he has to do and we did it again."