Although he had words with Phil Dowd after being shown the red card, the official has confirmed he was not sworn at by Rooney, an offence which could have led to a longer ban.
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However, the Football Association are to write to Rooney, whose temper has been a worry to some within the English game, about his conduct after the former Everton favourite punched a corner flag while leaving the pitch.
An FA spokesman said here on Monday: "We have clarified with Phil Dowd that there was no abuse from the player after he was dismissed.
"In relation to the incident when he punched the corner flag, the referee did not see that and we have written to Wayne Rooney reminding him of his responsibilities."
Rooney will now be suspended for one match, the Premier League fixture against Aston Villa at Old Trafford, United's home ground, on April 5.
Manchester United manager Sir Alex Ferguson will be relieved that his player will miss just the one game as with Dimitar Berbatov suffering from a cracked ankle the Premier League and European champions could face taking the pitch with just one experienced striker in the form of Argentine Carlos Tevez.