David Moyes accused his players of schoolboy defending as Manchester United threw away a lead to crash out of the Champions League at the hands of Bayern Munich.
The small pocket of away fans inside the Allianz Arena started believing their team could pull off another shock when Patrice Evra scored in the second half to give United a 2-1 aggregate lead against the Germans.
But United's defence then switched off, allowing Mario Mandzukic to score just 22 seconds after the restart.
That goal triggered a United collapse. Thomas Muller and Arjen Robben found the net to seal a 4-2 aggregate win for Bayern which dumped Moyes' men out of the competition at the quarter-final stage.
"It's the sort of thing you learn as a schoolboy once you score a goal, make sure you don't concede," the United manager said.
"You get into position and do your job. We had concentrated so fabulously well throughout the game.
"The players had done tactically well. Their positioning was good and they did their jobs.
"For us just to give it up on that moment, the goal up, was really disappointing."
Bayern dominated most of the play, ending the match with 63 per cent possession, but they could not find a way past David de Gea in the first half despite 13 attempts at goal.
Indeed it was United who had the better chances in the first half.
Wayne Rooney was the guilty party as he raced onto Darren Fletcher's pass, only to dally on the ball in the box before fluffing his shot.
The England striker, who played the game after having a pain-killing injection in his toe, then missed an even easier chance in the second period from eight yards.
Moyes insisted before the match that he was not gambling with Rooney's long-term fitness by fielding the player, but after the match he admitted the striker's performance was not up to scratch.
"I thought at times he was having a struggle striking the ball on some occasions," the Scot said.
"I was concerned that he hadn't trained all week and he had taken an injection.
"But he is so vital a player to us, especially with Robin van Persie out (injured).
"But he just had a couple of opportunities and he couldn't quite take them."