Derby head coach Steve McClaren believes his team need to learn a lesson despite a 2-1 victory over Barnsley which dealt a big blow to the visitors hopes of avoiding relegation.
First-half goals from Jeff Hendrick and Johnny Russell put McClaren's side in control, but a late reply from Nick Proschwitz set up a nervous final 10 minutes.
That had looked unlikely when Derby sprayed the ball around confidently in the first half, with Hendrick putting them into a 34th-minute lead when his 25-yard shot deceived Luke Steele, who watched the ball creep inside his right post.
The match then looked over when Russell's long-range strike looped off team-mate Craig Bryson to beat Steele in the 42nd minute, but Barnsley were better in the second half and Proschwitz 's precise finish in the 80th minute gave them hope, although Russell had a penalty saved a minute later.
McClaren knew it should not have been so close, and said: "The last 10 minutes were very unnecessary and shows we still have a bit to do with this team.
"When we control a game like that, play the football we do and create the chances we do, we need to be more ruthless and it nearly cost us in the end. So what could have been a harsh lesson was in the end just a lesson that we need to carry forward and take into the play-offs.
"To create that many chances and only score two was unbelievable. I couldn't fault the performance and the attitude, the only thing I could fault was we didn't get the third goal.
"When you are on top and you've got them down, you have to make sure you finish them. But we didn't, we let them back up and gave them a chance, and against different opponents that might have cost us."
The defeat leaves Barnsley four points from safety with two games left, but manager Danny Wilson still believes his team can pull of a great escape.
"It doesn't really change anything, we've always needed to win games and the next two games we've got to win," he said.
"It's as simple as that. Everyone will be writing us off, we are down in everybody's eyes and that's understandable. But we have six valuable points to play for and who knows what twist of fate is waiting on the last day of the season?
"We have to genuinely believe we can be the recipient of a good result on that particular weekend and stay up, but it will need two wins. You know from experience that on the last day of the season peculiar things happen.
"We've had some very good displays in recent weeks and that gives me belief, it really does. And we have some very good characters in the dressing room who will give it everything."
Wilson also backed Steele despite his mistake for the first goal, saying: "I don't think Luke saw it until late and then thought it was going wide, but he's been outstanding this season and that's why I won't be critical of him."