And, despite being on the back foot for large periods of the game, Hornets boss Quique Sanchez Flores was delighted with his team's progression to the fourth round.
"We are very happy because we are in the next round and that was the target," said Flores, whose team bounced back from consecutive defeats against Tottenham and Manchester City over the festive period.
"We respect the Cup and we try to put out the best team that is possible. We try to be competitive in every competition so for us it is a very happy day."