Chris Smalling scored as Manchester United beat rivals Manchester City . Win sends Louis van Gaal 's side Five points clear of the Citizens in third . Manchester United now sit just one point of Arsenal who occupy second . Smalling is confident of chasing down both them and leaders Chelsea . READ : four things Van Gaal has done to transform United 's results .
Chris Smalling scored as Manchester United beat rivals Manchester City . Win sends Louis van Gaal 's side four points clear of the Citizens in third . Manchester United now sit just one point of Arsenal who occupy second . Smalling is confident of chasing down both them and leaders Chelsea . READ : Five things Van Gaal has done to transform United 's results .