A 43rd-minute Greg Cunningham goal has given Bristol City a 1-0 lead over Watford at half-time.
The opening 10 minutes of the game were a scrappy affair, with both sides giving away a number of fouls.
Fernando Forestieri had the first real chance of the game on 12 minutes, but after a neat piece of skill his shot was blocked for a corner.
Watford were doing most of the pressing but were struggling to find a way through the hosts' defence.
Instead, it was Manuel Almunia who was called into action on 20 minutes, palming away a firm header from Liam Fontaine.
Alexandre Geijo had a chance with a snapshot after a Forestieri cutback, but was unable to find the target.
It was the struggling Bristol who opened the scoring with two minutes remaining in the first half, Almunia misjudging a Cunningham cross and seeing the ball go in off the post.
