Watford's Moussa Sissoko scores with a header at Middlesbrough
Moussa Sissoko's headed winner gave Watford only their second win in 11 Championship games to increase the pressure on Middlesbrough manager Michael Carrick.
The former France international midfielder was unmarked to power home the only goal and make it five defeats in six games for the home side, who were booed off by the Riverside Stadium crowd at full-time.
The win means the Hornets leapfrog above their opponents, who only came alive after the introduction of striker Delano Burgzorg at half-time.
The Dutchman went close to an equaliser three times and Rav van den Berg hit the post as Watford held on for the three points.
The meeting of two sides managed by former Manchester United team-mates Carrick andTom Cleverley saw both in dire need of a win, both having lost four of their previous five games to slide out of play-off contention.
Having won the reverse fixture at Vicarage Road earlier in the season, the Hornets were seeking their first league double over Boro since 1989-90 and after weathering early pressure which saw Tommy Conway shoot tamely when handed a chance by poor defending, they became a real danger on the counter-attack.
Giorgi Chakvetadze twice went close and Edo Kayembe wasted the best chance of the lot as the home side found themselves on the back foot.
Carrick lamented his side's frequent defensive errors in losing at Sheffield United in midweek, but his pleas went unheeded as Sissoko was allowed a free run and leap at Imran Louza's corner five minutes before half-time and planted his header firmly home.
Carrick sent on Burgzorg, surprisingly omitted, at half-time and Boro perked up, although the substitute missed chances to level.
Watford pushed hard for a second, Chakvetadze forcing two good saves from Mark Travers while Louza ballooned a great opportunity over the bar.
Boro gradually built up some pressure but Egil Selvik twice thwarted Burgzorg, the second save leading to a corner from which defender Van den Berg glanced his header against the post.
Watford substitute Tom Ince almost sealed it before the end, racing clear of the offside trap, only for Travers to save one-on-one, but Watford stayed strong to inflict a second successive home defeat on Boro.
'We're in a tough spot' - reaction
Middlesbrough manager Michael Carrick told BBC Radio Tees:
"There's no sugar-coating it, we're in a tough spot at the moment. You could smell it and feel it around today, and (we need to) face up to the reality that results haven't gone as we would like of late.
"I felt a lot for them because their attitude is top-class, honestly, they're desperate to do the right things and in sport when things aren't going for you and you're not in your peak mentality, the confidence dips a little bit and it becomes more difficult to play.
"In the second half, how we reacted and tried to create pressure and opportunities, I'm proud of them for because it's not a nice situation to deal with.
"It's totally my responsibility to deal with."
Watford manager Tom Cleverley told BBC Three Counties:
"The average age of our whole back four was 21 so it was a big call from me on the team selection. Mattie Pollock has been outstanding for us this season but I felt on Tuesday night (v Leeds) he looked like it had caught up with him a little bit.
"It was a decision I didn't take lightly with it being his home-town game but Kevin (Keben) came in and did fantastic.
"We were challenged in the last 15-20 minutes but I don't want that to cover over what I thought was a fantastic performance. It was by no means backs to the wall, we really should have been out of sight going into that 75th minute.
"We didn't manage it as well as we could and the defence was called upon, but I'm really pleased with the clean sheet."
