Nuno Espirito Santo is still waiting for West Ham's first League win after they were held to a gritty 1-1 draw in front of Vicarage Road's biggest crowd for six years.
The Hammers were booed off by a large section of their travelling support, who serenaded their under-pressure manager with a chorus of 'You're getting sacked in the morning' despite a dominant second-half display.
The Hammers are struggling to live up to their billing as Championship promotion favourites after letting a two-goal lead slip at Burnley and a shock home defeat by Charlton.
Here they fell behind to a brilliant goal from Watford's 19-year-old prospect Amin Nabizada and West Ham needed a freakish equaliser, from a dreadful mistake, to earn a point.
Nuno handed a League debut to 18-year-old defender Airidas Golambeckis, who was composed and assured.
But the Hammers had already survived Nabizada curling narrowly wide when the Hornets went in front after 19 minutes in spectacular fashion.
The Afghanistan international appeared to be crowded out in the box but he summoned the impudence to dink an exquisite, curling chip beyond Mads Hermansen and into the far corner.
It was a goal reminiscent of Gerard Deulofeu's trick shot at Wembley in the Hornets' FA Cup semi-final comeback against Wolves seven years ago, and West Ham were briefly rattled.
But when the East-enders rattled the collection tin, Hornets defender Kevin Keben gave generously.
Trying to shepherd the ball along the dead-ball line towards his own goal, Keben was robbed by Taty Castellanos and home skipper Mattie Pollock turned the ball into his own net from point-blank range.
The comical nature of the equaliser drained the early swagger from Watford and Keben's confidence evaporated for a time, although he did well to recover his composure later.
As West Ham warmed to their task after the interval, Arne Engels fired narrowly wide and only Pollock's last-ditch tackle thwarted Manor Solomon.
Much as they were on top, however, the Hammers still lived on their nerves and only Joel Veltman's critical deflection over the top denied Iker Bravo a late winner on a rare Hornets breakaway.
And much as Watford were forced back for most of the second half, they deserved their point to preserve head coach Alessio Dionisi's unbeaten start in the Championship.
Dionisi has been operating with such slender resources that he named two goalkeepers on the bench. He was well satisfied with the response to his weakened side's 5-1 hammering by league One Peterborough in the Carabao Cup in midweek.
Watford's Alessio Dionisi:
"I believe in Amin - I did not know him before I arrived but he played well in every pre-season game.
"I'm happy for him, I'm happy for my team and a positive result is even better. Now I wait for other players to score because it is impossible for Amin to score in every match.
"Before I asked him how many times he had scored in his career and he said zero - now he has two goals.
"One month ago, when we looked at the first three games, it looked terrible for us. But for me, every match is an opportunity for my team and now we have five points it feels better than a month ago.
"I believe in my team and I hope some new players will arrive. I don't know how many or when and I'm sure the club works hard for this. But it is impossible to play with only two centre backs in every match."
West Ham's Nuno:
"Pressure is on us every day. We are a big club and we are favourites to go up. We have two points from three games, so who's happy?
"But I believe - I trust my boys and I work very hard with them. We are building a team and things will change, I'm positive.
"The fans are the most important part of our club and I respect them so much. I understand everything, I respect every opinion.
"I just ask again, keep believing, keep trusting us, keep going and a win must come - hopefully it will be at the London Stadium on Tuesday. We need it.
"I have nothing to say about the players' attitude and belief, and they are more important for us moving forward, believing in the process and the way we are doing things. We're positive that we're going to click - we're going to do it."
