Poya Asbaghi thought Barnsley had a good chance of winning in the second half at Blackburn Rovers but was 'really disappointed' to lose 2-1.
Carlton Morris equalised against the run of play but, in a more even second half, the hosts scored the winner.
The second-bottom Reds remain seven points from safety and are winless in eight.
Asbaghi said: "I'm disappointed. We started well and created chances but we conceded. If they had scored again in the first half I wouldn't sit here and be disappointed because they deserved it.
"But we showed character to equalise and in the second half we had better control and they didn't counter-attack as much or create as many chances. We had a chance to counter-attack and I thought it was our time to score for 2-1 but instead to lose the ball and concede is really really disappointing. It's a tough goal to concede.
"We outplayed their press more times than before but we lost the ball in dangerous positions.
"We are improving in creating chances. But it comes at a cost where we have to make sure we also have a solid defence. We have to be brave on the ball and create chances but sometimes we lose balls in really dangerous areas. It is not until we are more smart on the counter-attack that we can actually win games."
Asbaghi praised his players for their workrate. He said: "You cannot blame the effort. I looked for the reaction when we went 1-0 down against the team that has the best form in the league. It would be easy to hide but the immediate reaction was for Romal Palmer to run and get the ball and players were applauding each other. I like that."
Callum Styles added: "It's disappointing to lose. We controlled a lot of the game. We created decent chances but I just think we needed to improve our rest defence for their counter-attacks which they hurt us on a couple of times. I thought we played quite well but they hurt us twice.
"We knew it was their gameplan to counter-attack but it was the little details that we needed to change and nullify their counter-attacks. We had some very good bits in the game which we can improve on."
Michal Helik came off after an hour having received treatment. Asbaghi said: "He first felt he could continue. I decided it was a big risk to let him play. He is important and we have 22 more games. Hopefully we substituted him in time so we don't miss him. I hope he will play on Monday but it's too soon to know."
