Troy Deeney has scored against his boyhood club Birmingham City to give Watford a 1-0 half-time lead at Vicarage Road in the Championship.
A scrappy and uninspiring half of football yielded few chances with both sides struggling to establish any consistent spells of possession.
Paul Caddis went closest for Birmingham, clattering the woodwork with a long-range effort but the visitors were otherwise largely toothless in attack.
The Hornets weren't much better but the decisive moment in the half came after 33 minutes when Deeney played the ball to Fernando Forestieri who drove to the line and pulled the ball back to his strike partner who had continued his run.
Deeney, inside the area, completely missed the ball with his first effort but he still had time to regain his balance and unleash a second shot which deflected past Darren Randolph and into the net.
Watford have been ahead but failed to win three times in the past four matches and will be hoping to reverse that trend and hold on to a much-needed three points.