Ferdinand was hit with a violent conduct charge by the Football Association for striking Hull's Craig Fagan in a Premier League game at Old Trafford on January 23.
Pure delight: Ferdinand celebrates Wayne Rooney's dramatic late winner against Manchester City last week
Had the 31-year-old accepted the punishment, he would have missed the Carling Cup semi-final second leg against Manchester City.
Instead, the appeal allowed him to play in the Red Devils' thrilling Old Trafford victory, a move that did not go down well with the game's governing body, who promptly added an extra match onto the automatic ban.
Battle: Ferdinand clashes with Carlos Tevez at Old Trafford
Yet United felt Ferdinand had a case and have opted to challenge, eventhough further matches could be added to the current four-gamesuspension if the disciplinary panel decides otherwise next Monday.
Liverpool star: Mascherano
The Red Devils are confident of success though, particularly as they have evidence to place before the panel that Mascherano got away without even being charged for what they believe was a very similar incident against Leeds in September, when the Argentina star caught Jermaine Beckford on the head.
'The concern is the word frivolous,' stated Ferguson.
'The two most experienced referees in the Premier League are Alan Wiley and Steve Bennett.
'They are under the same controls and the same directions. One says yes (Bennett), in the case of Rio, and one says no (Wiley), in the case of Javier Mascherano against Leeds United when he punched the player in the back of the head.
'When you see that example, we don't think our appeal was frivolous.'
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