Arsenal survived a scare at CSKA Moscow before advancing to the Europa League semifinals, where they'll be joined by Atletico Madrid, Marseille and Salzburg.
The draw for the semifinals will take place alongside the Champions League semifinal draw on Friday.
CSKA Moscow had cut Arsenal's aggregate lead from three goals to one before late goals from Danny Welbeck and Aaron Ramsey secured passage to the semifinals 6-3 on aggregate after a 2-2 draw on Thursday night.
The hosts gave Arsenal all they could handle early, as Petr Cech spilled a headed shot from Kirill Nababkin into the path of Fedor Chalov, who smashed it into the back of the net to give CSKA a 1-0 advantage at half-time.
Nababkin then doubled CSKA's lead early in the second half, pouncing on another rebound -- this time from a swerving Aleksandr Golovin shot from distance -- and volleying home to cut the aggregate deficit to 4-3.
However, Arsenal scored a crucial away goal in the 75th minute, Welbeck curling home a perfect first-time shot after a neat one-two with Mohamed Elneny left him with just Igor Akinfeev to beat.
Ramsey then added a late goal with a lobbed shot in stoppage time to secure a draw on the night for Arsenal.
Atletico Madrid suffered a 1-0 defeat away to Sporting Lisbon, but the result was just enough to allow Diego Simeone's men to go through 2-1 on aggregate.
Sporting seemed up to overturning their two-goal deficit from the start as Jan Oblak was forced to make a fine diving save to deny Sebastian Coates in the 11th minute.
But the Portuguese side got a goal back as Bruno Fernandes lofted a cross out of Oblak's reach and Fredy Montero headed home from a tight angle.
However, Atletico had the better of chances to increase their lead in the second half, and though a goal didn't come, they still saw out the game to advance.
The shock of the day came in Austria, where Salzburg defeated Lazio 4-1 to overturn a 4-2 deficit from the first leg and go through 6-5 on aggregate.
After a goalless first half, Ciro Immobile scored for Lazio 10 minutes after the break to increase the Italian club's aggregate lead to 5-2.
But Salzburg pulled a goal back through Munas Dabbur's deflected shot less than a minute later, before three goals in a four-minute span overturned the tie.
First Amadou Haidara lashed in a shot from 25 yards, and two minutes later Hee-Chan Hwang pounced on a defensive miscue to score at the near post and put Salzburg ahead on away goals.
Stefan Lainer headed home from a corner soon afterward to provide some breathing room, and Lazio could not find the goal that would have send the game to extra time.
Marseille also overcame a first-leg deficit to eliminate RB Leipzig with a 5-2 victory in their second leg.
Leipzig held a slender 1-0 advantage from the initial meeting in Germany and they got a crucial away goal through Bruma just 64 seconds into the second leg.
Yet the tie was soon level as Stefan Ilsanker scored an own goal and Bouna Sarr added a second before Florian Thauvin's effort gave Marseille an aggregate lead prior to half-time.
Leipzig hit back through Jean-Kevin Augustin, and at that point they would have progressed on away goals, only for Dimitri Payet and Hiroki Sakai to score and make sure of Marseille's progress via a 5-3 aggregate success.