After a goalless first half, the Hornets took the lead through Andre Gray before a quick-fire double from Coventry turned the game on its head, but the hosts responded well in the face of adversity with goals from William Troost-Ekong and Ismaïla Sarr giving them the win.
The result sees Watford rise into the automatic promotion places, a point off league-leaders Reading, while Coventry rest just one place above the relegation zone heading into the international break.
Story of the game
Coming into the match, Vladimir Ivić made three changes to the side which beat Stoke on Wednesday evening, with Troost-Ekong replacing Ben Wilmot in defence, James Garner taking Nathaniel Chalobah's spot in midfield, and Gray making his first start of the season in place of João Pedro.
Visiting manager Mark Robins also switched up his pack with Dominic Hyam and Tyler Walker coming in for Kyle McFadzean and Mark Godden respectively.
On a picturesque autumn afternoon at Vicarage Road, a minute's silence was observed prior to kick-off, this being Watford's closest home game to Remembrance Sunday.
With three minutes on the clock, Christian Kabasele brought down Callum O'Hare to give Coventry a free-kick in a good position on the edge of the area. Ben Sheaf stepped up to strike, but it was smashed straight into the wall.
Moments later, Watford conjured their first chance of the match, building confidently out from the back and eventually finding Sarr on the right flank. The forward whipped in a good cross which just evaded Gray but did bounce over to Tom Cleverley, who just had to stretch too much to hit the target.
The Hornets were knocking the ball around with some real poise and self-assurance. A long pass from Craig Cathcart unleashed Gray behind the Coventry defence and the 29-year old skipped past Michael Rose with ease, but his attempt to cut the ball back for Sarr arriving late was dealt with in the nick of time by Hyam.
It was misplaced passes and sloppy touches here and there that prevented Watford's intricate possession play from translating into the genuine goalscoring opportunities it deserved, and Coventry began to grow into the game, themselves enjoying good spells with the ball.
Striker Maxime Biamou had the chance to strike from the edge of the area with 20 minutes gone but skied his effort, much to the relief of the Watford defence who had handed him the opportunity through a lapse of concentration.
The Sky Blues continued to push, and thought they'd taken the lead when an excellent cross from Ryan Giles on the left teed the ball up perfectly for Biamou to head home, but the Frenchman stood in disbelief as his shot flew just wide of the post.
Garner supplied a vicious low free-kick into the Coventry box on 27 minutes and Troost-Ekong threw all of his leg at it, but after some pinballing the back line were able to clear their lines. It felt as if the deadlock wasn't far from being broken, but it wasn't yet clear in which direction the balance would tip.
Certainly, Coventry were providing a sterner test than perhaps had been anticipated by Ivić and his players. The hosts were at risk of falling foul of the unpredictability of the Championship once again after dropping points at Wycombe Wanderers and Barnsley last week.
About 10 minutes before the break, Gustavo Hamer made a bursting run down the right and supplied a low cross looking for Walker at the back post. The forward seemed certain to score, but Ben Foster made himself big and, with help from Kabasele, managed to thwart the shot. A let-off for Watford's outfielders, who were letting the game slip out of their control.
Watford piled on the pressure as the game headed towards half-time. A sumptuous flick from Garner set Kiko Femenía free to run towards the byline, but his whipped cross was headed away by Rose with Cleverley lurking just behind. Simon Hooper's whistle followed shortly: 0-0 at the break.
The visitors began the second half brightly, with Hamer picking up a loose ball on the edge of the area and threading O'Hare through on goal, but Foster produced a fine save to keep the scores level. Leo Østigard then headed over from the resultant corner.
But it was Watford that scored first when Ken Sema embarked on one of his characteristically powerful runs down the left before supplying a driven cross into Gray who couldn't miss from a couple of yards out. Deserved or not, the balanced had tipped in favour of the Hornets.
Moments later, a poor touch from Østigard allowed Sarr to latch onto the ball before the Senegalese forward was felled cynically by the on-loan Brighton & Hove Albion defender. The Hornets claimed Østigard was the last man and demanded he saw red, but Hooper was unmoved, and the 20-year old went into the book.
After a shaky period, Coventry came close to equalising on the hour mark when Giles weaved his way into the box and struck a strong effort towards goal, though Foster was untroubled.
But they didn't have to wait much longer for their equaliser, and it came in bizarre fashion, with Hamer scoring a header from outside the box. And less than 60 seconds later the Sky Blues found themselves in the lead thanks to an assured finish from Walker who latched onto the set-up from strike partner Biamou.
The chaos continued as Coventry's advantage was cancelled by Troost-Ekong, powering home a header from Garner's whipped corner to even the scores. Almost immediately from kick-off, Gray was then set through on goal and bore down on goalkeeper Marko Marosi, but the Slovakian got down well enough to save the shot.
It really was one of the most bizarre 5-minute spells that this writer has seen at any football match.
The contest was anyone's for the taking now, with both sides probably feeling they were deserving of victory. Ivić made the bold move of bringing off goalscorer Gray for skipper Troy Deeney in a bid to give his side the edge in the final third.
Fellow forward Sarr was granted a half-chance to get his side back into the lead as the ball dropped to him on the edge of the area with 77 minutes gone, but the effort was high and wide from the 22-year old.
The Hornets where given the perfect opportunity to regain their lead with just under 10 minutes of regulation time to play. Sarr geared up a shot from just inside the box but saw his effort blocked by the hand of O'Hare; Hooper pointed to the spot immediately and without hesitation.
To his credit, the young forward insisted on striking the penalty himself despite regular taker Deeney also being on the pitch, and his self-assurance paid off as he coolly sent Marosi the wrong way — 3-2 with just over five minutes to play, the hill was always going to be steep for Coventry, and the game petered out towards its conclusion.
Takeaways from the match
Difference in quality ultimately prevails
These two teams had an entire division between them last season, but if any void still exists it wasn't so obvious on the pitch here. Truth be told, for the most part Watford didn't do enough to trouble their visitors and nearly fell foul of their own naivety.
However, the ability within their ranks did shine through in the end. Sarr and Sema in particularly proved handfuls all game long and played crucial roles in two of their three goals; the players, and their head coach, kept their heads in the faces of adversity and, similarly to Wednesday's victory over Stoke, managed to come away with all three points.
Coventry battle well
For all that Watford may look at themselves for the troubles they encountered in this match, their visitors deserve recognition. They played some good football and, particularly in the first half, defended well enough to limit any opportunities the Hornets had considerably.
On the whole, Robins should be pleased with his side's showing, though the nature of defeat was perhaps concerning and the table doesn't lie — the Sky Blues are 21st after 11 games and need to improve.
Ken Sema (Watford)
The hero on Wednesday evening when his powerful, direct run set up Sarr for the winner, Sema once again showed his quality here and gave Coventry's right side a host of problems all game long.
It's one of the perks of the 3-5-2 formation that has been questioned by fans in recent weeks — it gets the most out of the Swede and his wing-back partner Kiko Femenía on the other side.
Watford: Foster; Troost-Ekong, Kabasele, Cathcart; Femenía (Ngakia 67'), Garner (Chalobah 87'), Capoue, Cleverley, Sema; Sarr, Gray (Deeney 74').
Subs not used: Bachmann, Sierralta, Quina, João Pedro.
Coventry City: Marosi; McCallum (Dacosta 90'), Rose, Hyam, Østigard, Giles; Hamer (Allen 90'), Sheaf, O'Hare; Walker, Biamou.
Subs not used: Wilson, McFadzean, Kelly, Bakayoko, Bapaga.
Following the two-week international break, Watford will travel into central London to face Queens Park Rangers.
Meanwhile, Coventry will host Birmingham City in a west Midlands clash.