Παρατηρητές διαιτησίας στα παιχνίδια του πρώτου προκριματικού γύρου του Europa League ορίστηκαν ο Γιώργος Μπίκας (Χαλκιδικής), ο Γιάννης Τσαχειλίδης (Πειραιά) και ο Μιχάλης Κουκουλάκης (Ηρακλείου). Πρόκειται για τους εξής αγώνες ρεβάνς:
9 July 2018, 16:00 – Yerevan (Vazgen Sargsyan anvan Hanrapetakan Marzadasht)
FC Gandzasar Kapan (ARM) – KKS Lech Poznań (POL)
Referee: Mohammed Al-Hakim (SWE)
Assistant Referee 1: Mehmet Culum (SWE)
Assistant Referee 2: Stefan Hallberg (SWE)
Fourth Official: Bojan Pandzic (SWE)
UEFA Referee Observer: Michális Koukoulákis (GRE)
UEFA Delegate: Peter Oskam (NED)
19 July 2018, 20:00 – Chișinău (Stadionul Zimbru)
FC Zaria Bălți (MDA) – Górnik Zabrze (POL)
Referee: Rəhim Həsənov (AZE)
Assistant Referee 1: Yaşar Abbasov (AZE)
Assistant Referee 2: Akif Əmirəli (AZE)
Fourth Official: Rauf Cabbarov (AZE)
UEFA Referee Observer: Ioánnis Tsachilídis (GRE)
UEFA Delegate: Jevgeņijs Miļevskis (LVA)
19 July 2018, 22:00 – Domžale (Športni park Domžale)
NK Domžale (SVN) – NK Široki Brijeg (BIH)
Referee: Antti Munukka (FIN)
Assistant Referee 1: Jonas Turunen (FIN)
Assistant Referee 2: Jukka Honkanen (FIN)
Fourth Official: Mohammed Al-Emara (FIN)
UEFA Referee Observer: Geórgios Bíkas (GRE)
UEFA Delegate: Johny Vanspauwen (BEL)