The Reds trailed to a goal 10 minutes in and although they improved after the break and levelled with 10 minutes left, aninstantreply by the home side was enough to secure the win.
Walcott almost hit aninstantreply, in what was one of his first meaningful contributions, and there followed a pulsating period in which Aguero fired wide, Hart saved from Van Persie and Zabaleta hit the post from 20 yards.
York were close to aninstantreply when David McGurk flashed a header wide from a Chris Carruthers corner, only for Oxford to go up the other end and double their lead when Constable powered his way through to beat Ingham with a fierce left-foot drive for his 26th goal of the season.