On-loan striker Darren Huckerby eased the effect of David Johnson's absence with a debut goal to earn Nottingham Forest a valuable point at Vicarage Road.
Johnson has undergone knee surgery that may rule him out of the rest of the Nationwide Division One season.
And the 24-goal striker was badly missed by a Forest outfit lacking any creativity during the first 45 minutes.
But Manchester City forward Huckerby, brought into the starting line-up by manager Paul Hart in place of Johnson, pounced on a loose ball shortly after the interval to deny Watford a victory which had rarely looked in doubt following Heidar Helguson's first-half finish.
Huckerby's debut almost got off to a terrible start inside the first minute when Watford's Marcus Gayle was allowed space to swing a dangerous cross into the box, but Allan Nielsen guided his close-range shot into the arms of goalkeeper Darren Ward.
Helguson also threatened with a volley from the edge of the box which Michael Dawson did well to deflect away from goal, and the Icelandic striker made no mistake with a second opportunity in the 13th minute.
Jamie Hand worked his way down the right wing and crossed to the back post where Helguson rose unchallenged to force a header past Ward.
Five minutes before half-time, Helguson almost deepened Forest's problems but his shot from the edge of the box drifted wide of the post with Ward beaten.
Reid and Helguson both wasted decent openings during a slow start to the second period but Huckerby struck in the 66th minute to silence the home crowd.
Marlon Harewood's shot from the edge of the box was parried by Chamberlain and Huckerby was first to the rebound, firing the ball into an empty net.
Ward denied Hand as Ray Lewington's side continued to push forward but the visitors came closest to snatching a win their performance hardly deserved when Reid's cross was hammered against the woodwork by Dawson in injury time.
Watford: Chamberlain, Ardley, Cox, Gayle, Robinson, Nielsen,
Hyde, Hand, Glass, Noel-Williams, Helguson. Subs: Vernazza,
Dyche, McNamee, Norville, Lee.
Nottm Forest: Ward, Thompson, Hjelde, Dawson, Brennan, Jess,
Scimeca, Williams, Reid, Harewood, Huckerby. Subs: Roche, Doig,
Bopp, Westcarr, Oyen.
Referee: A Hall (West Midlands)