UEFA Europa League – Semi-finals (First Leg)

26 April 2018

Arsenal – Atletico de Madrid
Referee: Clement Turpin (FRA, photo)
Assistant Referee 1: Nicolas Danos (FRA)
Assistant Referee 2: Cyril Gringore (FRA)
Additional AR 1: Ruddy Buquet (FRA)
Additional AR 2: Nicolas Rainville (FRA)
Fourth Official: Hicham Zakrani (FRA)
Referee Observer: Matteo Trefoloni (ITA)

Olympique de Marseille – FC Salzburg
Referee: William Collum (SCO)
Assistant Referee 1: David McGeachie (SCO)
Assistant Referee 2: Francis Connor (SCO)
Additional AR 1: Robert Madden (SCO)
Additional AR 2: John Beaton (SCO)
Fourth Official: Douglas Potter (SCO)
Referee Observer: Nikolai Levnikov (RUS)