"I cannot understand how such a fantastic group of people and such a terrific team that has done so well to get where we are now puts on a performance like that. It's incredible. I'm not surprised by the result after that performance and to give Burnley their credit they came here expecting an onslaught from us, but they didn't get it, they were allowed to play, we didn't close down, we didn't attack efficiently.
"We were over-passing the ball for some ridiculous reason, the energy and the passion that is usually seen from Watford just wasn't there and it is one of those things where I now have to think about shaking it up again."
Watford got back into it with a late Danny Shittu goal but Boothroyd said: "Dan came up with a goal but the game was gone by then, we should have done far better than we did. We should have stuck to the game plan and if we had have done that we would have won this game comfortably, but we didn't.
"If the ethic isn't there from a team of such fantastic willing workers, if it's not there for whatever reason then you'd have been surprised if we'd have won. If we'd have won it would have been an unfair result. We didn't defend properly and to lose 2-1 at home, to concede two goals is very, very disappointing.
"It was a sub-standard performance and it was like that from minute one and it didn't get any better. It was an awful spectacle, an absolute shocker."
Just as it had been for Steve Cotterill in 2004, Owen Coyle's first Burnley win came at Vicarage Road and he was delighted with it. "To come here and give the level of performance we did as a team made this victory merited," he said after the game.
"Whoever comes to Watford will be put under pressure because they are a good side. They threw the kitchen sink at us in the end, but we stood up and dealt with that and I thought we looked really fluent when we had the ball.
"From start to finish we gave every ounce of effort and nothing we did was a surprise. We took what we did in training into the game. I asked the players to come and believe in what they could do because I've seen with my own eyes that they are good players.
"We know we can pass and move the ball and score goals, and I thought the two goals were fantastic. Long may that continue.
"I don't want to single out individuals because this was very much a team effort. I've stressed that from day one and we want to foster that spirit and keep it going."
Coyle did though speak about Joey Gudjonsson who came off the bench at half time and scored our crucial second goal. "Whatever has happened previously has happened, but I have looked at Joey and he has trained well," the manager said.
"What he can do is score goals. He could have done that twice against Stoke and when he came on here their goalkeeper made a terrific save. But eventually it is a terrific finish. The pass from Robbie Blake is sublime, but Joey showed great composure.
"I have been in that situation myself and they are very easy to miss. But he still had a lot to do after going round the keeper and that probably summed up our overall performance, which was all about composure.
"You only need to look at Joey's body language and his demeanour on the park. He is delighted to be doing his bit for Burnley Football Club and that's what I ask from him. That's the same for everybody. We will always forgive mistakes, but I want those players to give every ounce of effort and tonight they did, to a man."