Leonardo Jardim blamed individual errors after a 4-1 defeat at home to RB Leipzig on Tuesday saw Monaco crash out of the Champions League.
With the Ligue 1 champions now guaranteed to finish bottom of Group G, having failed to win any of their five matches, last season's semi-finalists cannot even qualify for the Europa League.
A pair of Jemerson gaffes left Monaco 2-0 down in the opening 10 minutes and those errors were followed by captain Radamel Falcao clumsily giving away a penalty, leaving a frustrated Jardim to bemoan his side's lapses in concentration.
"We paid a lot… for our mistakes," Jardim said. "We were not at the level required of a competition like this.
"The disappointment is very strong, we had the goal of bouncing back and winning tonight.
"And then our opponent was successful: four goals in three shots on target - but we were not up to the Champions League this season."
Leipzig coach Ralph Hasenhuttl was thrilled to keep his team's qualification hopes alive ahead of a matchday six clash with group winners Besiktas, although the Bundesliga team will, at worst, be in the Europa League.
"I can say without exaggeration that this is our best performance in the Champions League," Hasenhuttl said. "We started as I wanted, making beautiful transitions.
"The only problem is Marcel Sabitzer's injury. He has a very bad [dislocated] shoulder and went straight to the hospital.
"We knew the result in Istanbul [1-1 between Besiktas and Porto]. A Besiktas victory would have been better for us. But we stayed very focused on our game.
"From now on we no longer have our destiny in hand. But we are sure to play in Europe in 2018.
"And I can also promise that we will win our last match. We can be proud of our efforts."
A brace from in-form Germany international Timo Werner helped Leipzig collect their first ever away win in the Champions League.
"Timo was great. He proved that in a one-on-one he is a world-class player," Hasenhuttl added of his star forward.
"It is very rare that he does not score in this situation. He asked me to come off because he felt tired."
|Messi to miss Argentina´s upcoming friendlies|
|Dolphins say Hayes tore ACL attempting to avoid roughing-the-passer penalty|
|Modric deserved FIFA Best award – Ramos|
|Thibodeau open to potential Butler trade|
|Modric wanted Ronaldo, Messi at awards ceremony|
|Brewers´ Yelich active after elbow hit|
|Anthony on coming off Rockets´ bench: Whatever I have to do to help this team win|
|Raiders coach Gruden says Mack trade was hard on players|
|Bale lauds ´unbelievable´ Modric after FIFA Best triumph|
|Ronaldo, Messi lacked respect with FIFA Best awards snub - Capello|
|New Zealand the benchmark but England can win World Cup - Mitchell|
|FIFA Best Award a dream come true for Modric|
|Lakers a long way from Warriors, warns LeBron|
|Milner pokes fun at Salah´s Puskas Award win|
|Josh Rosen to replace Sam Bradford as Cardinals starting quarterback|
|Kaymer: Home-course advantage crucial to Europe hopes|
|Marta and Pedros win FIFA Best awards|
|I want to be in Toronto - Kawhi Leonard focused on Raptors, not future|
|Messi and Ronaldo lead FIFPro World XI as Salah and Neymar miss out|
|Knicks´ Kristaps Porzingis ´itchy´ to return but won´t commit to 2018-19 season|
|Modric beats Ronaldo and Salah to FIFA Best prize|
|49ers confirm ACL tear for QB Garoppolo|
|Salah beats Bale and Ronaldo to Puskas Award|
|Deschamps wins FIFA Best Men´s Coach award|
|Law to leave Windies for Middlesex role|
|Sunderland terminate Ndong´s contract|
|Spalletti warns rejuvenated Inter against complacency|
|Ryder Cup 2018: Figo in town as USA arrive in style|
|Browns name Baker Mayfield starting QB|
|Chelsea need to be more versatile, warns Giroud|
|Paris Saint-Germain FFP case referred by UEFA back to CFCB Investigatory Chamber|
|Busy Bertens ready for bed, Muguruza gains Wimbledon revenge|
|Hart ready if England come calling - Dyche|
|Ryder Cup 2018: An honour and a burden - the unique challenge of captaincy|
|Hibino beats Bouchard again at the Tashkent Open|
|Falcons lose Ricardo Allen for season|
|Mbappe three-match ban stands following appeal|
|Tomic wins first Tour-level match since Wimbledon in Chengdu|
|Ryder Cup diary: Scoreboard shocker, captains tight-lipped|
|Mourinho will spawn lots of managers - Lampard|
|Furyk outlines Woods´ Ryder Cup motivation|
|Tiger doesn´t scare Team Europe - Bjorn|
|Ryder Cup 2018: Team USA profile|
|Woods winning ´incredibly special for golf´, says Poulter|
|Grealish commits to Aston Villa with five-year deal|
|Ryder Cup 2018: Four reasons why Team USA will win|
|Herrera ready for return - Mourinho|
|Bellew determined to prove doubters wrong against Usyk|
|Lewandowski and Boateng´s professionalism impresses Kovac|
|WATCH: Sheepish Murray comically drops commemorative plate in China|
|Cech: Arsenal have forgotten how to win Premier League titles|
|Lemar must adapt to Atleti style, says Simeone|
|Toulon to appeal suspended points penalty|
|AFE rejects Miami plan for Girona-Barca|
|Messi and Ronaldo to decide world´s best young player|
|Ryder Cup 2018: Talisman Poulter key to European hopes|
|Pogba hits out at critics who ´create drama´|
|Barcelona to appeal Lenglet red card|
|Ryder Cup 2018: Team Europe profile|
|Patriots´ Gronkowski threatened to retire if traded to Lions|
|Ryder Cup 2018: Four reasons why Europe will win|
|Tigres and Monterrey condemn violence that leaves fan in intensive care|
|Williams baffled by coach´s claim he sent her US Open final signals|
|Ryder Cup 2018: A sporting spectacular you cannot afford to miss|
|Cricket Australia closes investigation into Moeen claim|
|Zlatan impressed by ´MVP´ singer|
|Modric hoping to complete FIFA and UEFA double at Best Awards|
|Mickelson never doubted Woods would win again|
|Woods looked like Tiger of old in 80th PGA Tour win|
|Chelsea were too slow against West Ham - David Luiz|