Monaco's players let their heads drop as they crashed out of Europe after a catastrophic first-half display against RB Leipzig on Tuesday, the club's vice-president has said.
With Porto and Besiktas having drawn earlier, Monaco knew victory over Leipzig, followed by a win in Portugal in their final Champions League Group G game, would take them through despite just two points from their opening four matches.
But last season's surprise semifinalists saw that ambition wrecked as they conceded four goals in the first 45 minutes at the Stade Louis II and were defeated 4-1.
"We're hugely disappointed. They have messed up the European campaign. In football, there are difficult times, and this is one of them. I didn't like that the players' heads dropped so quickly," Vadim Vasilyev told reporters.
"Two years ago, we were knocked out of the Europa League, and the next year we were Champions League semifinalists. We shouldn't draw conclusions this evening.
"We have to pick ourselves up from this defeat."
Monaco, three down with Timo Werner striking twice, appeared to have found a way back into the game when Radamel Falcao struck two minutes before the break.
However, another defensive lapse allowed Naby Keita to score the visitors' fourth seconds before the interval, snuffing out Monaco's hopes of a comeback and ending their hopes of even third place.
"This year, in this group, we have paid dearly for our mistakes," coach Leonardo Jardim said.
"Also we haven't been up to the standard of such a competition, with three defeats at home and two draws away."
Jardim, who saw key players including Bernardo Silva, Benjamin Mendy and Tiemoue Bakayoko depart over the summer, added: "The board knows that this can happen.
"It's cyclical. You have to respect the development and the progress of the players. Next year, we'll come into this competition better prepared than today."