The in-form Smith Rowe registered the 100th league goal of Arteta’s tenure with a low drive from outside the box after 56 minutes.
Gunners captain Pierre-Emerick Aubameyang had a first-half penalty saved by Ben Foster following a poor challenge by Danny Rose on Alexandre Lacazette – and the Hornets goalkeeper produced another fine stop to keep out Gabriel’s header shortly before half-time.
Watford were fired an early warning when Bukayo Saka had an eighth-minute finish ruled out for offside at Emirates Stadium.
The Hornets’ first attempt did not arrive until the 40th minute but Joshua King squandered the chance to earn a late point, shooting into the side-netting after pouncing on a mix-up between Aaron Ramsdale and Ben White.
The visitors’ afternoon was made worse as Juraj Kucka was dismissed for a second yellow card late on and defeat left Claudio Ranieri’s side 17th, two points above the relegation places.
It is a sixth victory in eight Premier League games for Arsenal, who move up to fifth – level on points with fourth-placed West Ham.
Arsenal continue to build momentum
At the end of a week in which three Premier League bosses have lost their jobs, Arsenal appear to be reaping the rewards for standing by Arteta following a disappointing start to the campaign.
An eighth-placed finish last term was followed by three successive defeats at the start of this season but the Gunners, unbeaten in 10 matches in all competitions, have real momentum going into the international break.
Aubameyang endured a frustrating afternoon and should have put away the initial chance prior to Saka’s disallowed goal, before seeing his spot-kick saved after Rose had needlessly wiped out Lacazette.
Making his second league start of the season in the absence of the injured Thomas Partey, Ainsley Maitland-Niles effectively commanded the midfield alongside Albert Sambi Lokonga while Saka tormented left-back Rose throughout.
But it required a moment of quality from Smith Rowe to end Watford’s resistance and the England Under-21 international, omitted from Gareth Southgate’s latest senior squad, now has five goals in his last eight games in all competitions.
Aubameyang was ruled offside in getting a boot to Martin Odegaard’s goal-bound shot as the Gunners were unable to extend their advantage, however the hosts were rarely troubled at the back.
Kucka’s long-range effort after 85 minutes stood as Watford’s sole attempt on target – though Ranieri’s side felt aggrieved at Smith Rowe’s eventual winner which arrived after the Hornets put the ball out of play due to an injury.
Things do not get any easier for the Italian’s struggling side after the international break, with fixtures against Manchester United, Leicester City, Chelsea and Manchester City to come.