Chris Smalling insists his mistakes are behind him going into match against Arsenal

Chris Smalling has made a promise to Manchester United fans, insisting that the red card he received in the recent derby defeat was a one-off - and won't happen again. The Red Devils defender came into criticism following two stupid first-half bookings at the Etihad Stadium earlier this month, which contributed to the disappointing 1-0 loss against Manuel Pellegrini's side.