
Following a poor first half for both sides, Sargent’s stunning flicked finish six minutes after the break gave the visitors the lead as he opened his Premier League account in style.
Following a bizarre break in play as several floodlights went out, Sargent’s night to remember continued as he drilled in from distance to double his side’s advantage in the 74th minute.
Watford’s bad luck continued as Emmanuel Dennis was sent off four minutes later after collecting his second yellow card.
The hosts’ miserable evening was complete when Juraj Kucka’s stoppage time own goal handed the visitors a 3-0 win.
Norwich’s fourth win of the season lifted them to 17th with 16 points from 22 matches. Watford dropped to 18th, with 14 points from 20 games.