The fine was for his reaction to referee Mike Dean after being dismissed for a second bookable offence.
The card looked harsh and the youngster went spare at the ref before being taken away to the changing room, he has since made an apology to Dean for his actions.
Rafael pleaded guilty to a misconduct charge, which could have brought a further suspension, in addition to the one-match ban he will serve by missing tomorrow's encounter with Birmingham.
However, a specially convened panel, which heard evidence from both Rafael and Sir Alex Ferguson by video link, opted against lengthening the ban, leaving the player free to face Blackpool on Tuesday.