Farid El Alagui said the mistakes Brentford made in the Capital One Cup defeat to Derby County last night cost them dear.
The Bees were knocked out of the competition in the Second Round stage by the Championship side last night.
The hosts went a goal up inside the first 20 minutes after Brentford had started well and then added two more before half time.
Two goals in the second half gave them a 5-0 win.
Only Scott Barron started against Derby having started in the 1-0 Sky Bet League One win against Walsall on Saturday while Farid, Sam Saunders and Jake Reeves, who came on as substitutes in that match, also started.
Uwe handed a Brentford debut to Development Squad winger Josh Clarke, who started in midfield, and brought on Alfie Mawson for his debut late on.
Fellow Development Squad players Luke Norris and Aaron Pierre also got game time.
Farid said a changed team did not excuse the performance and the mistakes made.
He said the players had to learn from them to prevent them happening again.
“There were lots of changes, but that is no excuse,” said Farid, speaking to Bees Player: Match Day Live after the match.
“We didn’t start the game too badly but were a bit shy with the way we tried to pass the ball.
“We made mistakes and at this level you can’t do that, it costs you a goal.
“We showed them a bit too much respect, allowed them to play through our midfield and that is a killer against this type of team.
“It was not the best way to start the game.
“We had a plan, we tried to stay compact and together but they found a way to play through us.
“Maybe we were too deep and couldn’t hold the ball.
“We need to learn quickly about these types of mistakes, we can’t do them again.”
Farid said Derby’s quality in front of goal was evident.
“When you play a Championship team you know it will be one chance, one goal,” said the striker.
“They played well; their strikers played well and finished their chances.
“At this level if you allow them to come in to your box, it should be a goal.”
Farid has scored three goals in four substitute appearances so far in 2013/14.
He missed most of last season with a serious knee injury and then part of pre-season.
He made his first start for 11 months in last night’s match.
“My fitness is still coming,” he said.
“I am quite pleased with the games I have had.
“I had 60 minutes on Saturday and another hour tonight.
“It is good for me.
“The more I play the better I feel.
“I want to stay fit as much as possible.
“Hopefully I will be ready for all the games coming.”
Farid said he was pleased winger Josh Clarke got his First Team chance.
“I am pleased for Josh,” he said.
“He was very good tonight.
“He tried to play forward and with his pace he can beat anybody.
“He had a very good game on the ball, he was positive.
“I have played with him a few times, I know his quality.
“I am pleased for him that he showed what he could do at this level.”
Brentford’s next match is a Sky Bet League One match against Carlisle United at Griffin Park on Saturday.
The Bees have won their first three home matches this season and sit fourth in the table with eight points.
“We have a few days to recover,” said Farid.
“The Carlisle game will be different but again they are tough opposition.
“We will be ready.
“The league is our business, we have to do well.
“It is another game at home.
“Griffin Park has to be a fortress for us, we need to win.”
The best bits of Bees Player: Match Day Live from Tuesday night will be available soon.