The Hornets did it the hard way, coming from behind after Isaac Price curled the Baggies into a 34th minute lead.
Crucially though, the home side were only behind for four minutes, levelling four minutes later through Imran Louza’s superb strike from the edge of the area that dipped over keeper Josh Griffiths.
Watford stepped up their performance levels after the break and scored what proved to be the winner 13 minutes into the second half through Rocco Vata.
Here are five talking points we’ve selected from tonight’s game. You can tell us what you think by using the comments section on this page.
Stats telling the full story
Some fans love stats, others hate them, but one tells the full story of Imran Louza’s impact on the game: a pass completion rate of 93% with 53 completed out of 57.
The majority of those (39 from 41) came in the first half in which he simply bossed the latter stages, getting into increasingly more advanced positions and scoring a fantastic equaliser.
How highly do you rate Louza’s importance to Watford?
Decisions decisions…
Gracia received plenty of criticism after selecting Moussa Sissoko and Edo Kayembe in his first starting XI at Sheffield United on Saturday.
While there was still no Kwadwo Baah in the line-up, Sissoko and Kayembe also had to settle for a place on the bench alongside him as Vata and, more surprisingly, Jeremy Petris came into the midfield quartet.
What did you make of Gracia’s starting line-up?
Chalk and cheese
The starts Watford made to each half were almost polar opposites.
They barely got out of their own half in the opening ten minutes as they largely stood off, allowing the Baggies to dominate possession, set the early tempo and ultimately fell behind for an eighth successive game.
The story couldn’t have been more different after the restart though; a high intensity, pressing game that resulted in opportunities before they took the lead.
How concerned are you by Watford’s continued slow start to games?
A dip in form
Young players can often be more susceptible to dips in form and Nestory Irankunda looks to be going through one currently, at least at club level.
The young Australian’s made several unforced errors and poor decisions in the first half and was taken off at half-time.
Is it time for Irankunda to come out of the starting XI for a spell?
The best of Bola (so far)
The absence of Caleb Wiley meant Marc Bola returned to the side and he delivered his best display in a Hornets shirt so far.
The left-back was often the recipient of Louza’s cross-field passes as the home side slowly grew into the first half, but it was after the break that he really came to the fore, capping his display with the run and cross that led to Vata’s goal.
What was your view of Bola’s performance?