Hull City 4
Watford 1
Hull win 6-1 on aggregateChampionship Play-off Final Hull City v Bristol City, Wembley, 24 May Live on Sky Sports 1, 3pm

Goalkeeper Richard Lee admits his blunder probably cost Watford a place in the Championship Play-off Final. Now Lee and his team-mates are bracing themselves for an inquest into a season that started so well but ended so poorly, with Aidy Boothroyd warning that many of the squad will not be at Vicarage Road next season.

The manager has promised to make sweeping changes, in personnel and to Watford's direct style of play, following a humiliating 4-1 play-off semi-final, second-leg defeat at Hull City.

In the wake of Sunday's 2-0 loss at home, it meant Watford went out 6-1 on aggregate and ended the season with just one win in their last 16 games.

Having raced to an eight-point lead at the top of the Championship before Christmas, when automatic promotion to the Premier League one season after relegation seemed a safe bet, it was a shocking decline.

And Watford's players were left stunned at the KC Stadium last night. Lee emerged from the away dressing room to say: "It's not great in there at the moment. We're all devastated because it was a game we know we could have won. Over the two legs we lost 6-1 and we were the better team in both legs."

Watford needed an early strike and they got it after just 12 minutes when Jobi McAnuff, Lee Williamson and Nathan Ellington combined with some neat inter-passing before Darius Henderson placed the ball wide to the right of goalkeeper Bo Myhill.

The goal rattled Hull, but Watford's hopes of meeting Bristol City at Wembley on Saturday week were dashed just before half-time.

Defender Jay DeMerit could only head a cross high into the air just inside the penalty area, which set Lee racing off his line to make a catch. By the time he realised he wasn't going to make it and started back-pedalling, Richard Garcia had headed over the stranded goalkeeper and 34-year-old Nick Barmby raced in to nod the ball over the line.

Lee said: "We went a goal up and we were on top but then we gave away a bad goal. I got caught in no-man's land and just couldn't keep it out. Had we gone in 1-0 up at half-time, then who knows what might have happened. That goal changed the complexion of the entire game.

"Up until then, they were getting restless, their fans were becoming irritated and the impetus was with us. I believe our legs and our fitness would have carried us through."

Instead, it was Hull who carried belief into a second half in which Boothroyd's decision to substitute defender Adrian Mariappa with striker Tamas Priskin was to prove decisive.

"It's not as if we had to worry about goal difference," said Boothroyd.

"We were chasing the game and you may as well get beat 4-1 as 2-1. We just went for it and unfortunately they were clinical in how they reacted."

Hull manager Phil Brown brought on Caleb Folan for 39-year-old Dean Windass, and it was Folan who headed Hull's second from a position where he would have been marked by Mariappa.

Former West Ham and Colchester midfielder Richard Garcia waltzed through Watford's defence to score the third two minutes from time, and Nathan Doyle completed the rout 60 seconds later with a deflected shot.

It was a poor reward for Watford who, as on Sunday, abandoned much of their traditional long-ball play to prove they can play effective football along the ground.

Boothroyd, regarded as one of England's most promising managerial talents when he took Watford up to the Premier League in only his second season at Vicarage Road, knows his reputation is now on the line.

He said: "We're all in it to win and we began the season with that intention. To go out in the semi-finals is particularly disappointing. But you reap what you sow, I think we've gone out because we deserved to go out. Now we need to change a few things.

"We certainly need to shift one or two people in or out, and I think we need to change the way we play.

"I thought in the last two games some of the football we played was outstanding, but without the end product.

"Now we've got to make sure we bounce straight back next season. I'm confident we can do that, absolutely. I won't be sulking."

The comeback begins tomorrow. "There will be an inquest," said Boothroyd. "And there will be change."