Louis van Gaal was left to rue Manchester United's failure to deal with set-pieces as they fell to a 2-1 Premier League loss at AFC Bournemouth.
The pressure has been mounting on Van Gaal after a toothless 0-0 draw against West Ham was followed by a 3-2 loss at Wolfsburg that ended their participation in the Champions League.
And the critics will be sharpening their knives again following Saturday's reverse at the Vitality Stadium – United's first league defeat since October.
The visitors fell behind when David de Gea failed to collect Junior Stanislas' corner that sailed straight in and, although Marouane Felliaini levelled before the break, former United forward Josh King completed a well-worked corner routine to settle the contest in the 54th minute.
"Two set-plays cost us like against Wolfsburg," Van Gaal told Sky Sports. "That is not normal for us because we give a lot of attention to organisation. They had a few variations and did it very well, but still it cannot be.
"We played rather well in the first half and I had the feeling we could win in the second half, but then a set-play and you are behind in the score and it is very difficult to have a revival.
"The players had done everything, but Bournemouth pressed on the ball in a fantastic way which made it difficult to get the equaliser or create chances."
Van Gaal refused to lay blame on goalkeeper for De Gea for his rare misjudgement and stated his focus was on how United could come back into the game.
"At half-time I spoke about how we have to do it in the second half and I don't talk about the past," he added. "I don't think that's any benefit for me or the players [dwelling] on something like that, we have to go on and I think that's more important.
"It's a rare error, but I think David knows it better than me."
The Dutchman accepts that criticism is sure to follow, but called on United's fanbase to show faith.
"It [criticism] is always like that. It is not new it is a matter of belief. Believe in the manager or not. That is the most important thing," he said.
"Last year the fans all showed their belief and that is the most important thing. For me the most important thing is the commitment of my players to perform as we have agreed and I can only tell they want to do that."
United are now winless in five in all competitions, leaving them three points off the summit, though Leicester City can move six points clear when they host champions Chelsea on Monday.
