Norwich kicked off attacking the river end goal and after five minutes there were shouts for a penalty when Simeon Jackson went down under a challenge from Martin Taylor.
Referee Nigel Miller waved play-on and after that watford mounted several dangerous counter attacks.
In the fourteenth minute one such foray into the City half led to a corner. After playing a one-two from the flag kick, Lee Hodson beat the Norwich defence with a cross which John Eustace did well to control before unleashing a fierce left foot drive from twelve yards, beating John Ruddy low to his right.
After twenty-two minutes Scott Loach dived to his right to palm away Andrew Surman's long range free kick. Two minutes later Danny Graham doubled the lead when he played a clever one-two with Marvin Sordell before beating Ruddy low to his left with a firm left foot shot from fifteen yards.
Ruddy kept Norwich in the game with a smart save to keep out a snap shot from Will Buckley. At the other end Jackson could only hit the side netting with a shot from an acute angle and Chris Martin headed wide under pressure from two defenders.
HALF-TIME: City 0 Watford 2
Seven minutes into the second half Jackson's neat back heel set up Andrew Crofts and his first time, right foot shot from eighteen yards beat Loach's dive to his right.
Adrian Mariappa failed to capitalise when Ruddy dropped a cross, putting his close-range header wide of the post.
This lifted the home side, but apart from a David Fox shot, well held by loach, the Watford keeper was largely untroubled, so it was no surprise when last season's top scorer, Grant Holt, replaced Jackson eighteen minutes from full-time.
He went close to an equaliser with a brave diving header, but two minutes later Mr Miller failed to penalise Watford for a 'foul' and, as play continued, Graham's angled right foot shot from seventeen yards deflected off Elliot Ward and a post to put the game beyond Norwich.
The Canaries should have had a penalty when Martin Taylor had both arms round Holt. And they did pull a goal back as the game entered four minutes of stoppage time, when Michael Nelson converted Crofts' low cross from the right, beating Loach low to his right with a right foot shot from twelve yards.
The referee continued to annoy manager Paul Lambert in added time, when once again he failed to award City a free kick, this one in a goal-scoring position for a 'foul' that looked even more blatant on the televised replay.
At the post-match press conference the City boss expressed disappointment with the manner in which his players had conceded the two first half goals, but was pleased with their second-half performance.
FULL-TIME: City 2 Watford 3