Substitute Tom Ince's 100th Sky Bet Championship goal crowned Watford's fightback in a thrilling 3-2 win at Vicarage Road which dented Norwich's revival.
Booed off at the interval after a lacklustre opening 45 minutes, the Hornets' improved display, which kept the Canaries rooted in the drop zone, was harsh on Philippe Clement's side.
Norwich twice went ahead and often played with enterprise which belied their lowly position, but they were undone by two-goal Luca Kjerrumgaard's twin headers and 33-year-old Ince's enduring poacher's instincts.
Fortified by four consecutive wins against Watford, including a narrow Carabao Cup victory at Vicarage Road in August, Norwich were brisk and threatening from the first whistle.
Emiliano Marcondes scooped an early chance just wide from 18 yards after only 20 seconds, and only Jeremy Ngakia's last-ditch tackle thwarted Josh Sargent's surge into the box.
But there was no stopping Sargent after 11 minutes as he stole in front of the dawdling Marc Bola on the far post to nod Oscar Schwartau's left-wing cross beyond Nathan Baxter.
It was the American forward's seventh goal in nine appearances against the Hornets and his third at Vicarage Road in 2025.
Watford - just one clean sheet since April - finally emerged from their dismally sluggish start as Kjerrumgaard's header from Imran Louza's corner was scrambled off the line with Giorgi Chakvetadaze just unable to apply a decisive touch.
Chakvbetadze, making his first start for nine months after a complex foot injury, was booked following a heavy collision with Canaries goalkeeper Vladan Kovacevic and the Georgian playmaker was forced to retire hurt eight minutes before the break - but not before the Hornets had emerged from their hibernation with an equaliser.
From another Louza corner, Mattie Pollock's header was beaten out by the diving Kovacevic but returned with interest by Kjerrumgaard, who nodded the rebound into the opposite corner for his sixth goal of the season.
Just when Watford appeared to be gaining a foothold in the contest, however, their defence went absent without leave again on the stroke of half-time.
Baxter stretched to keep out Sargent's low effort, but Marcondes seized on the loose ball and lifted a cross to the far post, where the totally unmarked Schwartau was free to restore Norwich's lead.
Ince almost replied for the home side immediately, whipping a decent effort just beyond the angle, but they had more joy from Kjerrumgaard's superb glancing header from Ngakia's cross 16 minutes after the break.
As the floodlights belatedly joined the party in gloomy conditions, Kovacevic made a miraculous save to keep out Mamadou Doumbia's header from point-blank range to deny Watford the lead for the first time.
Then City substitute Jovon Makama, clean through on goal, shovelled his finish wide as the game became more open.
But the Hornets' improvement was crowned by a brilliant goal 12 minutes from time, Moroccan winger Othmane Maamma's superb pass picking out Bola's run down the inside left channel and his low cross was swept home by Ince for his first goal of the season.
Norwich were not finished, and Baxter needed to parry Makama's fierce shot before Sargent's effort from the rebound was deflected over the top.
Watford's Javi Gracia:
"In the first half they were better than us, made more chances, scored more goals.
"The best thing for us was the reaction in the second half, when we were more aggressive, moved the ball quicker and we found a way to attack in a more constant manner.
"But I'm not so happy because, in my opinion, that's not the way we want to play. In the first 45 minutes it was too easy for our opponents to control the game.
"Tom's 100th goal in his career is good for him, but we need to find more balance in the team if we want to be more competitive.
"The level of the Championship is very high. Tom's experience helps the group but we need to have more composure and be more clinical.
"I'm more concerned about the first 45 minutes and the way we started the game. In this case we got the victory but I'm not so happy with the performance.
"If you don't play with the right distances between the lines, you give away too much space. We knew before the game that Norwich's position in the table was not a reflection of their quality."
Norwich's Philippe Clement:
"The result was not what we deserved today. That was clear to everybody, even the Watford bench.
"It was a game we took in hand from the first minute. In the first half, we dominated, we had good chances and we scored two good goals.
"At half-time we had the motivation to kick on in the second half but we didn't do that. Watford were more aggressive and we didn't come out in a good way. Our energy dropped. At 2-2, we didn't defend well and we didn't sick to our principles.
"There were decisive moments where we didn't make the most of it. We needed more luck, quality and composure to get the result we deserved."
