The Eagles will now face Shakhtar Donetsk in the semi-finals after the Ukrainian Cup Holders defeated AZ Alkmaar over two legs.
But what happened in that game and the other ties? Let’s round-up all the action as the competition reaches crunch time…
#### **Strasbourg hit back to stun Mainz**
Aside from Palace-Fiorentina, the other heavyweight quarter-final matchup was between Strasbourg and Mainz 05.
And with the Germans holding a 2-0 lead after the first leg in the Rhineland, Strasbourg would need something special to advance to the semis. They found it with a sensational comeback.
Sebastian Nanasi's close-range finish set them on their way before Abdoul Ouattara's powerful header got the hosts level on aggregate before the interval.
Amidst a frenetic home crowd, Strasbourg continued to pile forward after the break and got their reward when Julio Enciso tapped into an empty net after a flowing move down the right wing.
That was a relief for captain Emmanuel Emegha, who had earlier in the half seen his penalty well saved by an on-song Mainz ‘keeper Daniel Batz.
Yet he had the final say, producing a composed header from Enciso’s cross to finish the tie once and for all.
Strasbourg had fought back for a 4-2 win and now advance to their first European semi-final since their 1995/96 Intertoto Cup triumph.
#### **Vallecano survive scare**
La Liga side Rayo Vallecano were in an excellent position going into the second legs, after a 3-0 win over AEK Athens last week.
But the Greeks nearly pulled off a miracle in a thrilling second meeting on Thursday night. AEK started fast in front of 30,000 fans at the Allwyn Arena. A goal from Zini and a Răzvan Marin penalty bringing them within one goal on aggregate before half-time.
Zini then got his second after the restart to level the tie and at that point extra-time looked a real possibility.
But the Madrid side have shown resilience throughout their run to the last eight and did so again when captain Isi Palazón broke through the middle on the hour mark to restore their lead.
Despite AEK throwing everything forward in the closing stages, Rayo held firm with some resilient defending.
The Spanish club had only played European football once before this season, when they reached the quarter-finals of the UEFA Cup back in 2001.
#### **Shakhtar next for the Eagles**
Shakhtar Donetsk had also put themselves in a strong position to reach the semi-finals, after thrashing AZ Alkmaar 3-0 in the first leg.
And they navigated the return match in the Netherlands with relative ease to set-up a last four clash with Palace.
Shakhtar extended their aggregate advantage with rapid attacking break just before the hour, Kauã Elias producing a clever ball through for Alisson Santana to finish.
AZ had left Republic of Ireland forward Troy Parrott on the bench, but it was another substitute Isak Jensen who levelled the game on the night with a well-struck free-kick.
The Dutch side did get further consolation when Matěj Šín volleyed home, but Brazilian Luca Meirelles converted with seven minutes remaining to conclude the scoring. It finished up 5-2 to the Ukrainians on aggregate.
#### **UEFA Conference League quarter-final aggregate results;**
* **Fiorentina 2-4 Palace**
* Strasbourg 4-2 Mainz
* AZ Alkmaar 2-5 Shakhtar
* AEK Athens 3-4 Rayo Vallecano