Louis van Gaal watched Robin van Persie snatch a dramatic point for Manchester United against Chelsea and then branded the striker "stupid" for removing his shirt during his celebration.
Van Persie whipped off his shirt and flung it in the air moments after driving a 94th-minute equaliser past Thibaut Courtois at Old Trafford that cancelled out Didier Drogba's 53rd minute header.
In line with Premier League rules, referee Phil Dowd had no option but to show a yellow card to the striker for the celebration.
And while Van Gaal was delighted to see his team come away with a 1-1 draw, he was far from happy with Van Persie, who captained the side in the absence of the suspended Wayne Rooney.
"He did a stupid reaction after the goal," the United manager said.
"You can be excited but you don't have to pull your shirt off because then you have a yellow card. It is not so smart."
Van Persie has now been booked three times this season. If he is cautioned twice more before the end of 2014, he will receive a one-match ban.
The Holland striker, who had come in for criticism over his form before kick-off, admitted he let his emotions get the better of him when he scored the crucial goal.
"I know it's one of the rules that you have to keep your shirt on but sometimes you forget and everything comes together and the whole place explodes," Van Persie said.
"It was one of those fantastic moments and the main thing today is that we got something out of this game because we deserved it.
"It was a big relief for the fans, for the players and for everyone at Manchester United that we got the goal in the end. The whole stadium exploded and it gave us a big boost."
Van Persie squandered two good chances to score in the first half, but he showed his predatory instincts by sweeping home from six yards after Courtois had palmed Marouane Fellaini's header into his path.
United probably deserved a point after an impressive attacking performance, although Van Gaal will be concerned that his players did not take their chances, particularly in the first half.
Nevertheless, Van Persie was enthused by the comeback against the Premier League leaders.
"We showed everyone that we can compete with the best in England - I think soon with the best in Europe too," said Van Persie, who has now scored three goals this season.
"It's just a process and we are now in the middle of that process. It's getting better every day, we are improving all the time. Today showed that."
Asked if United can catch Chelsea, who remain the league leaders, he added: "Of course we can, there's a long way to go, nine, 10 games played and it's not even halfway.
"In my opinion we are better every day. In training and if you look at games you can see we are comfy on the ball and we are playing better. Now we have to stretch games longer. We extended that into the hour and we try to aim to play like that for an hour and a half."
Jose Mourinho seemed keen to avoid getting into trouble with his comments after the game, but it did not take much reading between the lines to guess his feelings about the decisions that had been made by Dowd.
"I have come from the flash interviews," the Portuguese, whose side are now four points clear at the top of the Premier League, said in his post-match press conference.
"I did five and in all five, the first question was my comments on the referee. I told them no comment, because when five ask the same thing, I don't need to answer.
"I prefer just to say that in my opinion, from where I was and reading the game, my feeling is that we had a good first half and a fantastic second half."