Watford lead Nottingham Forest 1-0 at half time at the City Ground.
Gabriele Angella's goal gave the visitors the lead just after the half-hour mark when he flicked the ball up before catching it on the volley.
Earlier in the game Forest should have taken the lead when Andy Reid found Danny Collins, but the defender could only hit the crossbar with the effort.
Troy Deeney went close with an effort after just four minutes when he curled a 20-yard shot just over the bar, before hitting the side-netting towards the end of the half with another chance.
