Pearson said: "He is an important player and brings qualities to the side that we need and that is he loves the pressure and loves to be able to make a fight of a game.

"He is always a handful to play against. He is still not at his best and the fact he has been able to play the number of games he has, contribute and score three goals in the last week bodes really well for us.

"I'm really pleased he is back fit and scoring goals, but also pleased we have a squad of players who are prepared to put their bodies on the line like they did."

Mariappa was shown a red card after receiving two cautions in quick succession and it resulted in Pearson making the decision to replace half-time substitute Nathaniel Chalobah with defender Craig Dawson on the hour mark.

Watford's manager apologised to the midfielder at the time and the 25-year-old was offered words of comfort by back-up goalkeeper Heurelho Gomes.

"I apologised to Chalo at the time and have done in front of the players, but to be fair to the lad he has a real emotional attachment to this football club," Pearson added.

"He understands. I would never do that to a player as a statement. It was a tactical change and a difficult one to do based on the fact he is a really good lad as well. He cares a lot about this club.

"To have to do that so early in the second half was not an easy thing, but my job is to try and find solutions. I thought that was our best one at that point."

While Watford thoroughly deserved all three points, Villa were poor from the first whistle and especially when up against 10-men for the final half an hour at Vicarage Road.

Playmaker Jack Grealish was ineffective and lost his cool a number of times in the second half; not least when he was dispossessed for the third goal.

Boss Dean Smith has endured a difficult December with Tyrone Mings absent with a hamstring injury and John McGinn out until March after fracturing his ankle.

He said: "We have won two from the last nine (league) games and McGinn played in seven of them. Mings in five so I won't label it on two players.

"There is no excuse. We have to perform better than we did in the first half. Thursday against Norwich we got attitude, character and application and in the first half (at Watford) we never got that.

"Unfortunately away from home at the moment our performances have not been very good and that is something we have to change straight away."