Ferguson, furious with referee Steve Bennett for signalling four minutes' injury time as United held on to a 1-0 lead, made the fist-pumping gesture when Cristiano Ronaldo scored the late second goal after a touchline run-in with Reading coach Wally Downes.

The FA confirmed they will study video evidence of the incident and ask Ferguson to explain his actions.

He is just back from a touchline ban after being fined £5,000 for using 'foul and abusive language' at Bolton.