David Moyes warned West Ham they needed to cut out individual errors after goalkeeper Lukasz Fabianski's costly mistakes in a loss to Liverpool.
With West Ham leading 2-1, Fabianski allowed a Mohamed Salah strike to squirm through his legs before being caught out of position for Sadio Mane's 81st-minute winner.
Despite threatening the huge upset at Anfield, West Ham are in the relegation zone, a point from safety.
While he backed Fabianski to recover from his mistakes, Moyes said the individual errors needed to stop.
"He has done great for us but, when you're in our position, when you make individual mistakes, you need to quickly get over them and get on with it and not let it happen again. That's the important thing," the West Ham manager said, via the club's website.
"He had a couple of really good saves. He had a couple of worldies when Liverpool hit a couple of good shots, but if I'm being honest, I think we should stop the first one as well.
"When you come to Anfield, I think you're always going to need your goalie to play well, whatever team you are, your goalie's going to need to play well because of their ability to get chances and shots.
"But Lukasz has done great for the club and he's done great for us, and it can happen, but for us to get where we need to go, we need to cut our individual mistakes out, whether it be the goalkeeper, the centre-half or a centre-forward missing a chance, we've got to be able to do that."
Issa Diop had cancelled out Georginio Wijnaldum's opener before Pablo Fornals gave West Ham a shock lead early in the second half.
Moyes saw plenty of positives from his team, but lamented their failure to take something from the clash with Liverpool.
"I have to praise the players for their effort and their commitment and even at the end, we looked like we were going to get a third right at the end. We have to take something positive from it, but taking no points means there is no real positive," he said.
"I have to say the players are getting better and doing a lot of good things, but we have to cut out the individual errors because they are costing us.
"I was pleased in a lot of aspects. I thought we did a really good job. I thought it was a game you come into and nobody has enjoyed coming here at the moment because of how well they're playing, but I thought, for long periods of the game, we did a decent job."