Kwadwo Baah's goal was his second of the season
Watford substitutes Edo Kayembe and Kwadwo Baah scored late goals to complete a second-half turnaround against Middlesbrough.
After a dominant first half, Boro broke the deadlock nine minutes into the second through George Edmundson's goal.
Watford manager Tom Cleverley made vital changes soon afterwards and midfielder Kayembe hit a venomous strike from the edge of the area past Boro keeper Seny Dieng, before German winger Baah volleyed in the winner.
With their fifth win of the league season the Hornets climbed to sixth in the Championship table, while Middlesbrough dropped down one place to ninth.
Boro boss Michael Carrick would have been pleased to see his side have 68% possession in the first half, and Finn Azaz guided a free header wide of the Watford goal in the first five minutes.
Following a swift counter-attack, Hornets striker Daniel Jebbison's cross on the half-hour mark fell kindly for Tom Ince in the box after Hackney's poor clearance, only for the winger to blaze over the bar.
Again on the counter, Moussa Sissoko fired a dangerous low cross into the box for Ince but he missed the ball altogether.
Emmanuel Latte Lath had a golden opportunity just before half-time to put the visitors ahead, nodding a looping Azaz ball over the bar, but Boro finally broke the deadlock in the 54th minute.
The industrious Azaz won a free-kick out wide and his low delivery squirmed between Ken Sema's legs, giving centre-half Edmundson the space to blast in a goal past the helpless Jonathan Bond.
Cleverley brought on three substitutes soon afterwards, which turned the tide completely.
Kayembe rifled a sweet left-footed strike from the edge of the area to ignite a comeback after being teed up by Baah on the right wing.
From barely having the ball, it became a Watford onslaught in the final 10 minutes and the impressive Baah hooked home a fantastic volley courtesy of fellow substitute Ryan Andrews' long throw.
Watford manager Tom Cleverley told BBC Three Counties Radio:
"It's a part of our game that we look like scoring in every single match. Our chance creation, the quality of chance we're creating and our goalscoring record is really up there this season.
"The goalscoring's good, the home form's good, now we just need to sort out the away form and conceding a too few many chances.
"Baah has been a fantastic impact for us in the main this season and Edo Kayembe's got four league goals from midfield.
"I'm really pleased by the impact they had and at the start of these weeks when you play three games in seven you utilise all the squad."
Middlesbrough manager Michael Carrick told BBC Radio Tees:
"That's football and it's such a tough place. We've got to look at ourselves. We've let the game slip away right at the end.
"For three quarters of the game we were really good. We've got to accept that and we've got to be better for it.
"Regardless of the chances, we had the game where we wanted it. We were up 1-0 in a really commanding position and we let it go."
