Burnley's 100th game in the Premier League wasn't a milestone to celebrate as their dismal away record was extended at Vicarage Road.
Looking to add to their solitary away point from 10 games on the road, Burnley's task was made significantly more difficult when they were reduced to 10 men as early as the sixth minute.
Jeff Hendrick's challenge on Jose Holebas was unneccessary to say the least, given threat levels were at a minimum with the ball loose in Watford's half.
The Greek full back was clearly injured from the tackle with replays suggesting that the Republic of Ireland international's studs went in over the ball.
Referee Michael Oliver didn't hesitate, brandishing the midfielder's first red card of his career.
Insult was then added to injury in Herfordshire as the Hornets stung Sean Dyche's side just minutes later with the fixture's opener.
The hosts worked the ball from the left full back position to Craig Cathcart in an advanced position down the right hand side.
The defender fed the ball inside to M'Baye Niang who, under very little pressure, swung the ball over to the far post where Troy Deeney got round the back of Matt Lowton to power a header home.
The visitors struggled to find a rhythm as they tried to come to terms with their numerical disadvantage and Walter Mazzarri's men went in search of their second of the afternoon.
They went close when goalscorer Deeney and provider Niang combined in a central position outside the penalty area but the French forward, on loan from AC Milan, was denied by Heaton who flicked the ball over the bar.
Holebas, who was greeted with jeers from the travelling supporters every time he touched the ball, posed a threat from the touchline and from his troublesome long throw Etienne Capoue tested Heaton with a volley.
Burnley struggled to impact in the final third but they were handed an opportunity to test Heurelho Gomes with a set-piece in dangerous territory.
Joey Barton, who has netted free kicks against Brentford, Preston and Southampton in his time with the Clarets, lifted the ball over the wall but Gomes was well-positioned to push the effort over the crossbar.
Niang had a swing at the ball inside the box, which Heaton gathered as Watford continued to probe before Mauro Zarate whipped an effort inches wide of the far upright after cutting inside and shifting the ball on to his right boot.
Ashley Barnes took one in the face to prevent Capoue's strike from rattling the net late on in the first half but there was still time for the Hornets to extend their lead before the interval.
Holebas was afforded far too much time and space to pick his head up and deliver the ball in to the box and Niang got across his marker to flick a header across Heaton and in to the far corner.
Burnley were vastly improved after the break and were unfortunate not to take a point home for their efforts in Hertfordshire.
Gomes did well to deny Michael Keane at the foot of his post when the Clarets defender towered above his marker to guide Scott Arfield's corner on target and at the opposite end, midway through the half, Heaton denied Capoue after Holebas had pulled the ball back from the byeline.
The England international stopper then made the save of the match moments later, throwing himself at Deeney's close range effort after the striker was picked out by Niang once again.
Arfield's fierce strike, which stung the palms of Gomes who was forced to claim the ball at the second attempt, was sandwiched in-between the introductions of deadline day signings Robbie Brady and Ashley Westwood, with the pair handed their debuts by boss Sean Dyche.
The away side showed plenty of character to get back in to the game and they were given their chance when Sebastian Prodl was penalised for handling Barton's shot.
Oliver pointed to the spot and, seconds after seeing his acrobatic effort hooked off the line by Cathcart, Ashley Barnes stepped up to tuck the ball in to the corner.
Burnley threw everything at an equaliser in a grandstand finish but couldn't quite find the finishing touch.
Brady was denied by Gomes while Barnes should've done better with a shot on the turn after the ball slipped through to him.
Deeney did have the ball in the net late on as the ball broke for him in the box but the goal was ruled out as Oliver spotted an infringement.