Arsenal boss, Mikel Arteta has warned the Gunners that their reunion with former boss Unai Emery will be tough.
Arsenal defeated Slavia Prague 5-1 on aggregate to book their place in the semi-finals of the Europa League where they will now face Villarreal.
Nicolas Pepe fired Arsenal ahead before Alexandre Lacazette doubled the lead from the penalty spot.
Bukayo Saka slotted home a third inside 25 minutes and Lacazette then added his second on 77 minutes.
Arsenal will now face Unai Emery in a two-legged semi-final and Arteta warned that his compatriot knows how to win this competition.
Emery won the Europa League on three occasions with Seville.
“It will be really tough,” Arteta told reporters after the game.
“They are a top team and Unai is probably the most successful manager in this competition. I am totally aware of that.
“We know the opponent we are going to be facing but we are now focused on Fulham.
“We won’t have any time to train anything, we will just make sure that the players recover and I activate them so they’re ready to go again.”