Thomas Tuchel acknowledged Chelsea are in danger of dropping out of the top four altogether after losing 1-0 to struggling Everton on Sunday.
Frank Lampard's Toffees snatched a potentially vital victory in their bid to avoid relegation from the Premier League for the first time, with Richarlison getting the decisive goal just after half-time.
Chelsea created several presentable chances but were denied by three wonderful Jordan Pickford saves as Everton held out under pressure at Goodison Park.
It was not so long ago that Chelsea appeared certain to finish in the top four, but they have won only once in their past four league matches, putting their position under pressure from Arsenal and Tottenham.
Tuchel insists he never felt completely safe, though.
“Of course, it was always like this," he told reporters when asked if they now face a battle to qualify for the Champions League.
"I said it many weeks ago that I didn't ever feel safe. We are never safe. By the way, if we are in a race for top one, top two, or top four, no matter what the race, the last four games to only have four points will never be enough, no matter which race we are in.
"We have to take care of ourselves. At the moment we don't get the points when we play well and deserve more and we lose when we play okay, this is a bad mixture."
Cesar Azpilicueta's dawdling on the ball ultimately led to Everton's winner, with individual mistakes becoming something of a theme in recent weeks for Chelsea.
Such errors, and how to eradicate them, have Tuchel at a loss.
"What can I do? The ball is free, then give a goal away. It is the worst thing that can happen to you in this atmosphere and situation. It happens too often, we struggle to play without big mistakes. That's why we struggle to have results.
"If there is something I can do I will try it but if I knew about it I would have done it before. I think, for me, the key is to have a clean sheet. Manchester United was a different game, more open, fluid, more spaces, and we finally scored late and conceded straight away.
"For me, this is more like the game against West Ham. The opponent defends deep, we struggle to find space in the first half, but against West Ham we had a clean sheet and played without any big mistakes.
"That gives us the chance to score late. If you run behind against an opponent like this, in this atmosphere and install emotion and belief in a stadium like this and the opponent's team, you struggle."
It was a bruising encounter, with referee Kevin Friend producing eight yellow cards in total.
The aggression displayed by Everton did not trouble Tuchel specifically, though he was critical of how the game was refereed.
"No, no, we expected [Everton to be aggressive]," he added. "It would have been nice to have a referee who was in charge of it – they got away with a lot. He decided to manage the game the way he did and I was not too happy with it, but it's his way.
"That is why it's important to not do any mistakes, instil belief, and to keep doing what we do on the highest level of focus. We struggled."