Arsene Wenger says Arsenal produced a "complete team performance" against Olympiakos to seal qualification for the last 16 of the Champions League.
France striker Olivier Giroud scored a hat-trick as the Gunners won 3-0 in Athens on Wednesday.
It means Arsenal reached the knockout stages for the 16th successive season.
When asked if it was one of his best European wins, Wenger said: "Yes, because we needed a perfect performance. I'm very proud."
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'The greatest escape'
Arsenal needed to win by two clear goals in Greece following a stuttering campaign which saw them lose their opening two games against Dinamo Zagreb and Olympiakos.
They were also hammered 5-1 by group winners Bayern Munich, but recovered to qualify with an accomplished display in Greece.
"I told you before the game it would be the greatest escape," Wenger told BT Sport.
"It is a fantastic achievement for us. When you look at who we've lost in the last three weeks, we've lost Francis Coquelin, Santi Cazorla and Alexis Sanchez among other long-term injuries. Not many people gave us a chance.
"We are a real team. In the dressing room this team is very close and you could see that again today."
'Our target is the quarter-finals'
Giroud saw the Gunners through with a clinical hat-trick comprising of a header, a low shot and a penalty.
He now has 13 goals this season and after admitting he was relieved to seal qualification, the striker looked forward to Monday's last-16 draw.
"We want to go as far as we can," said Giroud. "The target is to maybe reach at least the quarter final.
"It's the fourth year I'm here and we have never played a quarter-final. We will have a good rest and open the new page of the Champions League in February."
BBC Sport chief football writer Phil McNulty
Arsenal's brush with Champions League brinksmanship saw them crash out to a vastly inferior Monaco side last season - this time they embraced the pressure against Olympiakos and ensured a run that has seen the Gunners reach the last 16 every year since 2000 was not broken.
Arsene Wenger's side needed to pull out something special in a hostile Greek atmosphere to fight their way out of a corner as earlier losses away to Dinamo Zagreb and home to Olympiakos, two very average teams, put them on the back foot.
Come the hour come the man and this time it was often-derided Olivier Giroud who did the job with a hat-trick. What a bonus for Wenger to have the France striker looking so good, ably assisted by the excellent Joel Campbell, with Alexis Sanchez out injured and Theo Walcott not fully fit. How he needed them.
It was a relief for Wenger too, after his decision to prefer David Ospina to Petr Cech in goal against Olympiakos at The Emirates saw the Colombian drop the ball into his own net in a 3-2 loss that threatened to prove decisive.
This was a night, however, when no praise was too high for Arsenal and Wenger. The manager who never loses faith in his players was repaid with a place in the knockout phase of the Champions League on a memorable European night.
Who's through to last 16?
The eight group winners will be drawn against the eight runners-up, although teams from the same country cannot play each other.
Team who faced each other in the group stage also cannot be drawn together.
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