But, home fans could justifiably blame their unhappy afternoon on referee Steve Bennett who denied the home side two first-half penalties.
Norwich kicked off and only a reflex save by Pidgeley in the opening minutes denied the home side a dream start. Craig Fleming met Clint Easton's corner with a firm header but the Hornets keeper beat the ball away.
Watford won their first corner after 20 minutes but Marcus Gayle's header looped over the bar and a quickly taken goal kick gave Ian Henderson a shooting chance, but his long-range effort drifted wide with the keeper off his line.
The Hornets went ahead with their first shot on target after 24 minutes when Scott Fitzgerald slid in at the far post to finish Lee Cook's diagonal cross from the left.
Referee Bennett angered the home fans minutes later when Darren Huckerby was clearly tripped in the Watford penalty area, but was cautioned for an alleged dive.
Bennett then further frustrated City fans by waving away another penalty claim when Paul McVeigh appeared to be pushed over.
Four minutes into the second half, a slip by Malky Mackay left Fitzgerald with a clear run at goal but Robert Green blocked his shot, and Mackay made amends by getting back to complete the clearance.
Pidgeley then pulled off an acrobatic save to keep out Henderson's header from Adam Drury's cross, before Drury wasted a quickly taken free-kick.
In the 81st minute, Mr Bennett finally gave a penalty but it went to Watford and Green was booked when it was judged that he had failed to get a hand on the ball in a fifty-fifty situation.
Green guessed the right way, but could not get a hand on Neil Cox's spot-kick, which went inside the keeper's right hand post.
Jarvis scored his first goal for Norwich two minutes from time but it was too late to save the Canaries' 100 per cent home record.