Brentford and Watford are goalless at half time, although the hosts are down to 10 men after a red card for defender Jake Bidwell.
Brentford made a sharp start, and Watford keeper Heurelho Gomes had to be alert to prevent Andre Gray from having a clean strike at goal.
The Hornets took a while to settle into the game, but they almost took the lead in fortunate circumstances as a defender's clearance rebounded off Troy Deeney and fell inches past the post.
Brentford keeper David Button was then forced into a fine reaction save to prevent Odion Ighalo's flick from a Ben Watson shot flying into the net.
The away side created the better chances, and Deeney will feel he should have done better when he was found 12 yards out, as he took too many touches and allowed the Brentford defence to crowd him out.
Deeney then went close again, as he curled an effort inches wide from 20 yards out, before Brentford were reduced to 10 men as Jake Bidwell was shown a straight red card for a dangerous tackle.
