Watford boss Tom Cleverley has said the red card given to Kevin Keben at their game against Portsmouth on Monday "was a complete guess."
The Hornet's lost by one first half goal to the Blues and have now lost their last three matches.
In the game, Keben was shown the red by referee Sam Allison for bringing down Josh Murphy just outside the area, but Cleverley felt his man made a decent enough challenge.
"The sending off was a complete guess from the referee.
"This level of football when you make a big decision you have to get it right, Kevin (Keben) gets the ball and it's a really disappointing decision.