Arsene Wenger accused his Arsenal players of naivety after they fell to a 2-0 defeat to Barcelona on Tuesday and suggested they had failed to learn from past mistakes.
Lionel Messi struck twice in the second half for the defending champions to secure a significant advantage going into the second leg at Camp Nou in a month’s time.
Arsenal had chances of their own to take the lead at the Emirates Stadium, however, and Wenger was left to rue the way his side were subsequently caught on the break.
“We were naive,” he told BT Sport. “Similar to Monaco [in last season’s last 16], when it looked like we could win this game we gave it away.
“That [second goal] makes it realistically very difficult, if not impossible [to come back]. We have to go there and fight.
“It is difficult because I thought in the last 20 minutes there would be room to score. We had the chances but didn’t score.
“They are lethal. One thing we couldn’t afford to give them was counter attacks because they are very dangerous. That’s exactly what we did. We pushed too far in their half and got caught. That’s down to their quality as well.
“It’s too easy to blame I think you have to respect the effort the players put in. What is frustrating is that it looked like they might tire.
“I knew in the last 20 minutes we would have a chance to win the game if we don’t make any mistakes and that’s the frustration of the night.”