Match ends, Watford 0, Norwich City 3.
Norwich City scored three goals in the final 25 minutes to beat play-off rivals Watford and move to within four points of the top two.
Lewis Grabban scored a 65th-minute spot-kick after Miguel Layun brought down Wes Hoolahan in the area.
Moments later Cameron Jerome clipped a shot over Heurelho Gomes and Grabban swept home a third late on.
Watford, who drop below the Canaries to sixth, made few chances in what was their first loss in four games.
The defeat is not a disaster for the Hornets who, like Norwich, had won their last three games, but they could have opened up a six-point gap on their opponents and a decent play-off cushion with a win.
Instead, City registered a sixth success from eight under new boss Alex Neil and put themselves firmly in the automatic promotion race with a victory based on patience and organisation.
Neither side imposed themselves on the game for any prolonged amount of time, with Troy Deeney's shot across goal as close as anyone came to breaking the first-half deadlock.
Almen Abdi forced the first save of the afternoon when his scuffed half-volley went straight to Norwich keeper John Ruddy, but Vicarage Road was soon incredulous with referee Carl Berry's decision to award the visitors a penalty.
The home support, as well as Watford players, felt Hoolahan went down too easily when challenged by Layun, but Grabban kept his cool to slot into the corner.
Hoolahan then set up Jerome to curl home from 20 yards and, after Bradley Johnson's header drew a smart save from Gomes, Grabban was on hand to convert a looping Steven Whittaker cross into the net to round off the victory.
Watford boss Slavisa Jokanovic:
"We didn't make many chances - and neither did they.
"We had it more or less under control, but after the penalty we didn't have a reaction. We did not play with any plan and I'm disappointed with how we finished the game.
"People have told me it is a dive for the penalty and that he hasn't been touched. From my position I did not see it very clearly.
"Referees sometimes make mistakes. After they scored the penalty they scored a great goal. But our problem was the last 25 minutes because we made no reaction."
Norwich City boss Alex Neil:
"I'm making sure I'm fielding a team that suits the game. I felt today with Wes Hoolahan's trickery and Cameron Jerome's power and strength we would cause Watford problems.
"But ultimately it's about the guys performing on the pitch.
"I was as pleased with the first half as I was the second half. Watford are a free-flowing team and we made sure we came here and stifled what they were good at.
"We hoped they would become more expansive in the second half and leave space and that's exactly how the game panned out.
"It was difficult to see the penalty from where I was. Wes was running through bodies - I'd need to see it on the video. But the referee was a lot closer than I was."
- 15CathcartBooked at 53mins
- 6EkstrandSubstituted forVydraat 73'minutes
- 23WatsonBooked at 67minsSubstituted forTozserat 78'minutes
- 7LayunSubstituted forMunariat 69'minutes
- 27TetteyBooked at 38mins
- 4JohnsonBooked at 38mins
- 14HoolahanSubstituted forRedmondat 81'minutes
- 10JeromeSubstituted forDorransat 80'minutes
- 7GrabbanSubstituted forHooperat 89'minutes
- Carl Berry
- Shots on Target
Second Half ends, Watford 0, Norwich City 3.
Foul by Gary Hooper (Norwich City).
Gabriele Angella (Watford) wins a free kick in the defensive half.
Attempt missed. Daniel Tözsér (Watford) left footed shot from outside the box misses to the right.
Nathan Redmond (Norwich City) wins a free kick on the left wing.
Foul by Juan Carlos Paredes (Watford).
Bradley Johnson (Norwich City) wins a free kick on the left wing.
Foul by Juan Carlos Paredes (Watford).
Substitution, Norwich City. Gary Hooper replaces Lewis Grabban.
Graham Dorrans (Norwich City) wins a free kick in the defensive half.
Foul by Gianni Munari (Watford).
Attempt missed. Lewis Grabban (Norwich City) left footed shot from the left side of the box is high and wide to the right. Assisted by Bradley Johnson with a headed pass.
Goal! Watford 0, Norwich City 3. Lewis Grabban (Norwich City) right footed shot from the centre of the box to the bottom left corner. Assisted by Steven Whittaker with a cross.
Offside, Norwich City. Nathan Redmond tries a through ball, but Lewis Grabban is caught offside.
Attempt saved. Bradley Johnson (Norwich City) header from the centre of the box is saved in the bottom left corner. Assisted by Nathan Redmond with a cross.
Substitution, Norwich City. Nathan Redmond replaces Wes Hoolahan.
Substitution, Norwich City. Graham Dorrans replaces Cameron Jerome.
Cameron Jerome (Norwich City) wins a free kick on the right wing.
Foul by Gabriele Angella (Watford).