I thought we were very route one and that was purely because people weren't looking for the ball out from the backSteve Spooner.
The Hornets won last night's Third Round tie 1-0 thanks to a superb late free-kick.
But in truth, the hosts could have won by more had it not been for the heroics of Blues goalkeeper Zach Jeacock.
"Whilst we're disappointed to be out of the FA Youth Cup, we can have no real complaints because I was very disappointed with our performance," said Blues' Lead Professional Development Coach Spooner.
"But for an outstanding display by our goalkeeper Zach Jeacock it could have been a couple more before half-time.
"We looked like a team that don't play together and we were very disjointed.
"There was no cohesion and the players didn't seem to know what each other were doing and that was quite obvious.
"I thought we were very route one and that was purely because people weren't looking for the ball out from the back. We never got any fluidity in the game.
"I said to the players after in the dressing room that bravery comes in many shapes. It's not just about the tackle, it's when you're under pressure you've got to want to accept the ball and we didn’t play anywhere near as well as how we can play."
Other than a short spell during the first-half and another in the closing stages of fixture, Blues didn't consistently threaten, or get their game really going as they can.
Injuries had hampered selection and the fact several players had not been playing regularly for the Under-18s this season due to Under-23s involvement was a contributing factor in regard continuity, perhaps.
Watford were powerful and purposeful and Blues, at times, found that a struggle.
"We nearly got something at the end when we had a couple of good chances, but that would have been an injustice because they were far superior to us over the 90 minutes," admitted Spooner.
"There was a sneaky part of me that thought we weren't playing well but I've seen many a game over the years at every level where you don't play well, and you end up sneaking it and I thought that might be the case.
"But it was an outstanding free-kick from the Watford lad. And when you get beaten by goals like that you have to put your hands up."