Watford boss Adrian Boothroyd maintained his composure despite feeling his team had been the victims of what could be one of the worst penalty decision of the season.
Boothroyd had watched his side's heartening fightback after going a goal behind to Everton via Andrew Johnson's debut strike.
But when Chris Powell was wrongly adjudged to have handled a Tim Cahill cross late on, Mikel Arteta converted the spot-kick.
Boothroyd said: "It was human error, and I have to wait half-an- hour cooling-off time before I can strangle the referee.
"It was a mistake, no doubt about it, and it just shows referees and linesmen need technical help to avoid errors like that in the future.
