Watford edged a tight first half but Norwich went ahead on 51 minutes through Sargent's incredible improvised finish. The American turned in Teemu Pukki's low cross with a backheeled flick that looped over goalkeeper Daniel Bachmann. 

After a brief partial floodlight failure delay, Sargent superbly headed in his second goal from Milot Rashica's cross on 74 minutes. 

Watford played out the final 12 minutes with 10 men after Emmanuel Dennis was sent off for a second yellow card and they conceded again when Adam Idah's cross was deflected in by Juraj Kucka. 

Back-to-back victories move Norwich out of the bottom three for the first time this season and above Watford into 17th with 16 points. Watford are two points worse off but have played two matches fewer.