LONDON - Arsene Wenger hit out at his Arsenal flops as naive and suicidal after their defensive meltdown allowed Monaco to clinch a stunning 3-1 win in the first leg of their Champions League last-16 tie.
His men were widely expected to see off the French club and advance to the quarter-finals of Europe's elite club competition for the first time since 2010.
But instead, they are on the verge of a fifth consecutive last-16 exit following an incredible meltdown at the Emirates Stadium on Wednesday.
Geoffrey Kondogbia's first-half strike was followed by a cool finish from former Tottenham forward Dimitar Berbatov and, although Alex Oxlade-Chamberlain got one back for Arsenal in the 90th minute, there was time for Yannick Ferreira-Carrasco to score Monaco's third and leave the Gunners needing a herculean effort in the second leg on March 17.
In the heat of an immediate post-match press conference, Wenger is usually composed enough to deflect questions that ask him to criticise his players.
But after one of the most chastening defeats of his 19-year Arsenal reign - at the hands of the club where he made his managerial reputation - the 65-year-old was unable to conceal his frustration.
Taking aim at the careless play of Arsenal's defenders and the needlessly gung-ho attitude of the rest of the team, he said: "It was a horrible night. We missed chances and were a bit suicidal defensively.
"Their first goal was unlucky (for us) with the deflection but the second and third were suicidal. We cannot give away the third goal like we did.
"The balance wasn't right and when we lost the ball, we were exposed. I was most disappointed by our defensive naivety.
"It looks like we lost our nerves and our rationality. The heart took over the head and at this level, that doesn't work.
"Mentally, we weren't sharp enough to get into this game and we paid for it."
After getting their domestic form back on track in recent weeks, this was a return to the kind of mentally fragile and defensively sloppy display that has so often ruined Arsenal's hopes in Europe in the Wenger era.
The manager suggested his players may have taken victory for granted.
"I hope we weren't complacent, but when you have no sharpness, anything is possible," he said.
"We rushed our game. The difference was the mentality, we were too impatient because this is a game of 180 minutes."
Arsenal now need a three-goal victory to complete a miraculous escape in the return at the Stade Louis II.
But Monaco have not conceded three goals at home in any match this season, and no team have lost a Champions League first-leg knockout tie at home by two goals and progressed to the next round since Ajax in 1969.
"The task is massive now. The third goal makes it even more difficult," Wenger said.
"We have a much smaller chance but no matter how big the (chance) is, we will go for it."
Get MyPaper for more stories.