Dismissed by the Hornets in acrimonious circumstances just over a year ago, Silva has not enjoyed the kind of progress he would have expected during his maiden season in charge of Everton and his current club are now four points adrift of his former employers.
Andre Gray, introduced at the interval, provided the lone goal - his fifth in all competitions this term - by capping off Craig Cathcart and Will Hughes' classy combination in the 65th minute.
A game otherwise short on attacking quality ended with Everton mustering little beyond a misdirected Dominic Calvert-Lewin header and seeing Kurt Zouma sent off after full time for two yellow cards following a confontation with the referee.
They remain ninth, while Watford's second win in eight Premier League engagements lifts them to within a point of seventh-placed Wolves.
Have we met before? pic.twitter.com/pyhbeSrjkh— Watford Football Club (@WatfordFC) February 9, 2019
Troy Deeney, having fanned the flames of Silva's return with some incendiary comments about his former manager during the week, helped construct the game's earliest chance, cushioning a Daryl Janmaat cross into Etienne Capoue's path for a close-range shot that flew off Jordan Pickford and over the bar.
Kurt Zouma and Cenk Tosun both worked Ben Foster as Everton settled into the match, which remained goalless at the break following Gerard Deulofeu's poor connection with a Will Hughes cutback.
Gylfi Sigurdsson went closer within five minutes of the restart, instinctively lobbing a loose ball onto the top of the crossbar from inside the box.
But centre-back Cathcart proved the unlikely instigator of the decisive moment as his clever reverse pass set Hughes free in the box to square for an unmarked Gray, who made no mistake with the simplest of finishes for the winner.
Everton's back-to-back home defeats added to a growing sense of discontent at Goodison Park and this result - along with the rather limp performance that underpinned it - will have done little to assuage the supporters who are unhappy with the team's direction under Silva.
Hughes keeps his cool
He set up team-mate Deulofeu for a fine first-half chance and, having seen that good work go unrewarded, midfielder Hughes commendably returned after the break to lay on the pass from which Gray netted the winner.
The Englishman also gained possession on more occasions than any other Watford player in an industrious display.
Deulofeu reportedly attracted interest from AC Milan during the January transfer window but this was not a performance that would have increased his value.
The 24-year-old, facing his former club, passed up a promising opportunity to break the deadlock late in the first half and was ineffective on the ball going forward.
Key Opta Facts
- Watford have won their last three home Premier League games against Everton – the first time they've won three in a row against an opponent at Vicarage Road in the competition.
- Watford have registered three clean sheets in their last four Premier League games, as many as they managed in their previous 21 in the competition.
- Everton have lost seven of their last 11 Premier League away games (W3 D1), after losing just one of the six before that (W2 D3).
- Everton boss Marco Silva has won just three of his 13 Premier League games at Vicarage Road (12 games as Watford manager).
- Andre Gray's opener for Watford ended a run of 10 Premier League appearances without a goal for the stiker, his longest goal drought in the competiton.
- Will Hughes registered a goal involvement on home soil for the first time in his last 13 Premier League appearances, since an assist against Bournemouth in March 2018.