Poya Asbaghi said Barnsley 'played like children' in an 'unacceptable' performance despite gaining his first win as head coach with a 5-4 extra-time victory over Barrow AFC in the FA Cup third round at Oakwell.
The Reds led 2-0 at half-time against League Two opponents who had had a man sent off, but the hosts lost that lead and conceded levellers after going 3-2 and 4-3 ahead before winning in the added period.
Asbaghi told the Chronicle: "This is the FA Cup. It was a crazy game. I am happy that we won but I am really disappointed by the way we behaved at 2-0 up. When we go out in the second half we should kill the game but instead they scored a 2-1 goal after we lost the ball really easily. But it's still a free-kick from a very far distance and a nice goal.
"Our reaction after that is not acceptable. Barrow get a lot of energy from that goal and they started to believe, but we actually looked like children out there for a while. We were not taking responsibility. We were waiting for other players to do something.
"Barrow scored the only chances they had but it is not acceptable that they had those chances.
"We know we are young and we look really young out there, which we have to improve."
Barnsley's performance did not suggest they can bridge the eight-point gap to safety in the Championship but Asbaghi put it down more to complacency against lower opponents.
"I know people will feel that we cannot do what we need to this season after watching this game. But we have had better games than that this season, against tougher opponents. I don't expect the same performance in the Championship. I think it was mental in this game and I hope we can overcome this.
"We didn't approach the game in the correct way in the second half and it was down to mental things and underestimating the opponents, which I don't think will happen in the Championship."
Substitute Carlton Morris scored Barnsley's last two goals to secure the win. He said: "It's not ideal, the way the second half went, but the improtant thing is we fought back and got into the hat for the next round.
"I know this season hasn't gone the right way for us but we still like to have high standards and, at times, the defending today wasn't up to scratch. I understand there was FA Cup magic and they scored worldy goals and got good bounces, but they shouldn't have had those chances and it comes from us not being 100 per cent. It if you have a slight hint of complacency that is the sort of thing that can happen.
"It had to be game over at half-time. We can analyse a lot of things but also take positives, like scoring five goals.
"The manager told me to come on and make an impact then craziness started happening and I was thinking 'what is going on here?' I got the goals to get us the win which is all that matters.
"Give Barrow loads of credit. They were unbelievable at times. You forget they had ten men. For a League Two side with ten men to put up a fight like that is incredible."
Asbaghi said on Morris: "He was mature with good mentality, he wanted the ball and to take responsibility. If there was 11 players acting like Carlton Morris we would have won six or seven zero."
Barnsley were without, as expected, Cauley Woodrow and Michal Helik due to injury, but Clarke Oduor, Aaron Leya Iseka, Claudio Gomes and Josh Benson were also absent due to either injuries or Covid-19 which has hit the Oakwell camp in the last week. Coaches Jo Laumann and Ferran Sibila are also isolating.
Asbaghi said: "I don't want to get into specifics about who is out due to what. But it has been difficult for us. We have changed the starting 11 a lot of times in preparation, we had a new player out yesterday. We are struggling right now. It is a big question mark if they can come back for Wednesday.
"We had already players who played who are not 100 per cent fit so we will have to see how they react after 120 minutes. It's not ideal."
Joe Ackroyd, a 19-year-old midfielder, came off the bench for the second half of extra-time for his debut. He is from Barnsley and has been in the youth system since he was ten.
Asbaghi said: "Joe has done well in training and deserved his chance. He contributed what he could. I am disappointed with our mentality but I don't mean players like Joe on his debut, he made a good job."
Barnsley are now in the FA Cup fourth round draw which will be on ITV at about 4.50pm tomorrow. Asbaghi said: "We want to go as far as possible in this tournament, but before the next round we have important games in the Championship and they are my only objectives."
Morris added: "We would love a big dog at Oakwell. The fans could get a big day out."