Middlesbrough suffered a third straight home defeat as Tom Cleverley's strike earned Watford the points on Teesside.
The game's decisive moment saw Danny Graham's pass finished by Manchester United loanee Cleverley (26).
Boro pressed hard after the break with Tony McMahon firing a shot against the post, while Adam Johnson and Jeremie Aliadiere both went close, but Watford secured a third away win of the season.
Middlesbrough Jones; McMahon, Wheater (Capt), St Ledger, Bennett (Hoyte 55), Yeates (Arca 74), O'Neil, Digard, A Johnson, Lita, Aliadiere. Unused subs: Coyne (gk); Pogatetz, Grounds, Williams, Emnes.
Watford Loach; Doyley, Mariappa (Capt), Cathcart, Hodson, Harley, Cleverley (Ellington 64), Cowie, Jenkins, Lansbury, Graham. Unused subs: Bond (gk); Severin, Bennett, Hoskins, Henderson, Bryan.
Referee Scott Mathieson
Middlesbrough: Arca, 86, dissent.
Watford: Doyley, 37, foul.
Conditions: Cool and dry with a slight breeze.
Website Boro Man of the Match: Gary O'Neil