Images from the Champions League round of 16 second leg matches played on Tuesday
Arsenal failed to make the Champions League last eight for the fifth year on the trot on the away goals rule.
Monaco, who reached last eight for first time since 2004, 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.
Atletico win shootout to knock Leverkusen out
Atletico Madrid kept alive their dream of a second consecutive Champions League final appearance when they beat Bayer Leverkusen on penalties on Tuesday to claim a place in the last eight.
The Bundesliga side won last month’s first leg in Germany 1-0 and a goal from Atletico midfielder Mario Suarez in the 27th minute of the return match left the teams locked at 1-1 after extra time at the Calderon.
Both sides failed with two penalties before Leverkusen striker Stefan Kiessling fired the fifth spot kick over the crossbar to give the hosts a 3-2 shootout victory.
Knowing Atletico needed at least one goal to have any chance of going through, coach Diego Simeone sprung a surprise in his starting lineup by deploying attacking midfielder Cani instead of more defence-minded captain Gabi.
Roared on by the home support, Simeone’s men came storming out of the blocks but Leverkusen refused to be intimidated and Suarez's deflected effort that went in off defender Omer Toprak was their first shot.
Atletico had suffered a setback shortly before the goal when goalkeeper Miguel Angel Moya picked up a thigh injury and had to be replaced by Jan Oblak.
It was more of the same in the second half with a fired-up Atletico pressing forward without really threatening and a well-organised Leverkusen looking to hit back on the counter attack.
Atletico playmaker Arda Turan fired over with a volley on the run in the 69th minute after good work down the left from Antoine Griezmann and a Koke free kick evaded everyone and almost sneaked inside the post a minute later.
Tension was rising as the clock ticked down and Arda again went close in the 80th when he drew a good save from Leverkusen goalkeeper Bernd Leno.
The players were clearly tiring and chances were scarce in extra time.
Atletico midfielder Raul Garcia had the clearest chance in the 106th minute when he blasted an angled shot straight at Leno while Leverkusen captain Simon Rolfes lashed a long-range effort just wide in the 111th.
The draw for the quarter-finals is on Friday with holders Real Madrid, Bayern Munich, Porto, Paris St Germain and Monaco already through.
Atletico were beaten by Real in last year's final.