Alexis Sanchez's first Arsenal goal earned his side a nervy 1-0 victory over Besiktas of Turkey in London to squeeze them into the European Champions League for the 17th consecutive season.
Chilean star Sanchez repaid the first instalment of his $60 million transfer fee by tucking away a low shot in first-half stoppage time, but the hosts' inability to kill the game off made for a night of nail-biting tension at the Emirates Stadium.
Mathieu Debuchy's dismissal for two yellow cards meant that Arsenal saw out the last 15 minutes with 10 men, but although a solitary goal would have been enough to send the Turkish side through after last week's goalless draw in Istanbul, the hosts held on for a 1-0 aggregate win.
Arsene Wenger's side, who lost to Bayern Munich in the last 16 last season, will discover the identities of their group-phase opponents in Friday's draw.
In Spain, Athletic Bilbao qualified for the group stages for the first time in 16 years after coming from behind to beat Napoli 3-1 and 4-2 on aggregate.
Napoli looked set for a third group stage appearance in four years when Marek Hamsik fired them into the lead just after half-time.
However, awful defending from Napoli presented Aritz Aduriz with two simple chances to put the Basques in front before Ibai Gomez sealed the tie with a calm finish.
Athletic will now join three other Spanish sides, holders Real Madrid, Atletico Madrid and Barcelona, in Friday's draw.
Others to advance to the group stage are Malmo, Ludogorets and Bayer Leverkusen