Per Mertesacker has revealed that Arsenal were found wanting mentally in the first leg against Monaco at the Emirates where they succumbed to a 3-1 thrashing at the hands of the Ligue One club.
It is a stark revelation from the captain, whose team have been commended over the past few months for their ability to bridge the gap on Manchester City and bring the deficit down to a single point.
The Gunners secured an FA Cup victory over Manchester United last week and also completed four straight wins in the Premier League with their 3-0 thrashing of West Ham.
The north London club were very naive in the first leg, failing to balance their attacking intent with a defensive plan, and were dealt a sucker punch in the first half when the ball nestled in the net after a wicked deflection from Mertesacker.
The Gunners went two down in the second half but gave themselves a lifeline by scoring a beautiful goal through Alex Oxlade-Chamberlain, only to give away a third, ostensibly killing off the tie.
Olivier Giroud had a nightmare in front of goal and the striker is ready to bounce back from that ignominy, having scored three goals in his last three starts. However, Mertesacker's assessment of the squad's mental deficiencies is a marker for Arsene Wenger to work on and make sure that the Gunners are prepared for a better fight in the future.
"We know that first leg we weren't really up for it mentally. From the start you could feel that and, at times, we could feel that there was a bit of a pressure and we couldn't cope with that," Mertesacker said.
"We are coming out of a great week with two important wins. We have a good level of confidence. We have to face the truth, we have to show a different face but you need to embrace the challenge.
"You have to learn after a defeat, just the same as when you win. After that fixture obviously there were a lot of things that went not so well. We feel like, especially after that game, we moved on and improved a lot. That is why we are very confident that, even away from home, we can beat any team in the world," he concluded.