Jeremy Ngakia's sensational 77th-minute strike earned Watford a crucial 2-1 Sky Bet Championship victory over fellow play-off hopefuls Bristol City at Ashton Gate.
The visitors took a seventh-minute lead when Giorgi Chakvetadze's penetrating run down the right found Edo Kayembe, who pulled the ball back from the byline for Luca Kjerrumgaard to fire home from six yards.
But City were level in the 36th minute when Scott Twine powered a close-range header past Egil Selvik from an inviting Adam Randell cross from the right.
A draw looked the likely outcome, but Ngakia had other ideas, finding the top corner with a sweetly-struck right-footed shot when the ball was cleared into his path 25 yards out.
The result saw Watford leapfrog their opponents in the table and move to within three points of the top six. With some tough fixtures ahead, the Robins now face an uphill battle to achieve their play-off dream.
Gerhard Struber's side are badly hit by injuries to central defenders and named George Tanner and Neto Borges either side of recent signing Noah Eile.
Watford were able to recall defender Saba Goglichidze to a back four.
A compelling first half saw both sides create chances. Bristol City dominated possession but were often too deliberate in their build-up, while Watford had the pace to threaten on the break.
Ross McCrorie and Tomi Horvat forced diving saves from Selvik, but at the other end the Hornets went close to taking a 2-0 lead when Goglichidze's header from a free-kick rebounded off a post into the arms of City goalkeeper Radek Vitek.
Watford's Nestory Irankunda sent a swerving shot from 25 yards inches wide before Twine's equaliser and the final action of the half saw the impressive Horvat have an effort deflected for a corner.
Vitek had to come to City's rescue after 56 minutes as he stretched full-length to his right to tip an Imran Louza shot around a post.
Struber responded by sending on Sinclair Armstrong and Max Bird for Emil Riis and Twine.
Irankunda volleyed over from a Kayembe cross as Watford continued to threaten before Armstrong fired over at the other end from a Horvat pass.
Ngakia's thunderbolt stunned home fans.
Although McCrorie and Bird fired over in the closing stages and Bird had a header well-saved by Selvik, the hosts could not summon up another leveller and it was a hard-earned second win in charge for new Watford boss Ed Still.
Bristol City's Gerhard Struber:
"We think from game to game and the play-off race is likely to go to the final fixtures, so we are certainly still in it.
"Football is not always fair. We controlled most of this game and the boys have put in a good performance.
"We gave away the first goal too cheaply and our decision-making was not always good in the final third.
"The Championship is so close and we have to be very clear thinking when chances come along.
"That was missing from our performance tonight. Our level is good in most matches, but we have to make more of our opportunities to score.
"At the moment we are not doing well in the big moments of games at both ends. This result is a blow and we have to bounce back quickly, but we are capable of doing that."
Watford's Ed Still:
"Jeremy's goal was an absolute worldie. What composure to control the ball as he did and come up with that quality of strike.
"I told all the lads how proud I am of that performance. Everyone knows this is a difficult place to come and if we had a bit of luck at the end it was earned by heart and commitment.
"We've put a huge amount of work into attitude on the training ground and I have felt things getting better with each day.
"It's all about winning and how best to achieve that. Now the players deserve a couple of days off to relax with their families.
"From day one when I came in there was a feeling that we could make the play-offs. We can't promise that, but we can pledge to compete hard in every game until the end of the season and try our best to make it happen."
