The sides met a week ago, with the side from LaLiga triumphing 2-1 on that occasion - but the general feeling from within the Spanish club was that they let Arsenal escape to an extent and they should have been more ruthless in effectively ending the tie.
Nicolas Pepe’s penalty gives the Gunners a fighting chance, but they’ll need to be much-improved on home soil if they are to continue their European campaign and reach the final, against the likely opponents of Manchester United.
Two red cards, three goals and plenty of questions over the starting line-ups meant the first leg had several talking points and there’s little reason to suspect it’ll be any different in this decisive second leg.
Here’s everything you need to know ahead of the match.
When is the game?
The match kicks off at 8pm BST on Thursday, 6 May.
Where can I watch it?
The game will be shown live on BT Sport 2 and BT Sport Ultimate. Subscribers can stream the match via the BT Sport app and desktop website.
What is the team news?
The Gunners will be without Dani Ceballos after his red card in the first leg, while David Luiz is also sidelined through injury. Kieran Tierney and Alexandre Lacazette remain unlikely to feature from the start too, having only returned to full training on Tuesday.
Like Ceballos, Etienne Capoue was sent-off a week ago and will miss this game, suspended. Juan Foyth is a doubt after missing the weekend game, while Vicente Iborra is out.
ARS - Leno; Chambers, Holding, Gabriel, Xhaka; Elneny, Thomas; Pepe, Smith Rowe, Saka; Aubameyang
VIL - Rulli; Gaspar, Albiol, Torres, Pedraza; Chukwueze, Parejo, Coquelin, Trigueros; Moreno, Alcacer
Arsenal - 10/11
Draw - 14/5
Villarreal - 18/5
Villarreal to see out the job and Unai Emery to take a measure of personal revenge over an Arsenal team which remains wildly inconsistent and frustrating. Arsenal 1-2 Villarreal (2-4 agg).