A disappointed Quique Sanchez Flores insisted his Watford team took plenty out of their shock 1-0 loss to Preston in the League Cup.
Marnick Vermijl's eighth-minute goal was all the Championship outfit needed to stun the Premier League club at Deepdale on Tuesday.
Head coach Flores was left downcast over the result and rued the 75th-minute red card shown to Miguel Britos.
"We're disappointed with the result," he told the club's website.
"In the second half we had reached a point where we were close to the goal and we had two or three very clear attempts in different situations, but in this moment we received the sending off of Britos and after that it was very difficult to play 10 against 11.
"We tried to work hard, and we have learnt a lot. We tried to use this match to check players because it is very important to know how they are involved, so for us it is good information we have from the game.
"Some players haven't played an official match in a long time, only in pre-season, so it is important to know this kind of information because it is different to the information we receive every single day in the training ground."
Flores made numerous changes to his start XI to the team that drew 0-0 against Southampton in the league on Sunday.
The Spaniard said he found out a lot about his squad.
"The information we take after this match is good because we can correct the players," Flores said.
"When the players are playing every weekend it’s different because they feel involved in the team, they know the mechanism of the system and the shape.
"But sometimes when you are watching the match as a player outside the pitch it is a little bit different, it is a bit complicated sometimes to work well on the pitch.
"We will correct all the mistakes, and when you lose sometimes it is very easy to learn."
