Monaco were fortunate to reach the Champions League quarter-finals on away goals, Arsenal manager Arsene Wenger said on Tuesday after his team's 2-0 win at Louis II failed to overturn their first-leg defeat.
Monaco won 3-1 in London three weeks ago but were overwhelmed by a dominant Arsenal side in the return game, although Wenger was left to rue missed chances.
"We knew that it would be tough to score three goals but we did not seize our opportunities," Wenger told BeIN Sport.
"It's not a question of merit, it's a question of being efficient. We also made psychological errors in the first leg. Monaco were fortunate, we must congratulate them."
Arsenal defender Per Mertesacker, however, was critical of his side.
"The best team went through. Monaco deserved it because they played much better in the first leg. We played well today but it was a massive deficit and it wasn't enough tonight," the German said.
"We came here and tried absolutely everything and when you look at the game we could have scored more than two. Monaco deserve it and that's absolutely fine. They caused a lot of problems away from home. We have to admit that we regret the first game. But if we continue to play like that we'll do well in the FA Cup and the (Premier) league. But play as badly as we did in the first game and you're out of the Champions League. We tried to push until the end but Monaco held firm and they did not steal their qualification. Hats off to them," Arsenal striker Olivier Giroud said.
Arsenal went ahead in the 36th minute when Giroud fired into the roof of the net and second-half substitute Aaron Ramsey doubled the tally 11 minutes from time with a low shot.
"In the past we've played Bayern, Barcelona -- no disrespect to Monaco but we thought we had a good opportunity to qualify," Ramsey said.