Marcelo Bielsa rued Leeds’ profligacy in front of goal as they threw away two points at home to Derby in a 1-1 draw.
United bossed the vast majority of the contest and led through a Max Lowe own goal but could never get a crucial second despite all their pressure.
They even passed up the chance from 12 yards as Mateusz Klich missed a second-half penalty.
And for the third time at home this season Leeds let points slip away in the final stages, with Chris Martin equalising for Derby in stoppage time – their only shot on target.
“This has happened a lot of times to us, but today was the worst,” said Bielsa.
“They shot once all match. We created maybe 10 or 12 chances.
“We played 60 minutes very good, maybe the best since I’ve coached the team. But the last 15 minutes was flat.
“We couldn’t control the end of the match.
“When we lose a point in this way it’s difficult to admit reasons why. But we started to play long rather than line to line.”
Leeds’ start was electric and they peppered the Rams’ goal from the kick-off.
Patrick Bamford went close on a couple of occasions and it was no surprise when the hosts did break the deadlock on 20 minutes.
Bamford kept the ball in from a deep free-kick to tee up Stuart Dallas, whose shot was initially saved by Kelle Roos, but the ball rebounded into the path of defender Lowe and trickled into the net from close range.
Leeds could – and should – have built on that lead but Bamford hit a post before the hosts won a penalty when Bamford was felled in the box by Matt Clarke and Scott Malone.
Klich’s miss was undoubtedly the turning point of the game and despite County not having had any sniff of a goal all game, Martin’s fine finish from inside the box broke Leeds hearts.
Derby boss Phillip Cocu said: “When we concede a goal we have to make sure that we stay in the game.
“We stick to our plan. If we concede a goal, then we kill the game for five or 10 minutes.
“We did that, stayed in the game and scored an excellent goal.
“You have to give credit to Leeds because they are a big team with lots of quality and they put in lots of effort to get the ball back.
“I thought after 35 minutes we got back in the game, without creating any real chance. We kept the ball better so Leeds had to go back more.
“We kept believing that we could score and when we did score you saw what it meant to the fans. We have to use this boost going into our next game.”
As for Martin, it was the Scot’s first goal for the Rams since November 2017 following spells out on loan at Fulham, Reading and Hull.
Cocu added: “It was a great finish from Chris.
“If you look at him, he not only scored but he linked up well and had a good work ethic.
“He did a job for the team today. I was very pleased to see him score.”