It was a return to winning ways for Arsenal who only at the weekend lost 1-0 to Tottenham Hotspur in the Premier League.Arsenal took the lead in the 13th minute through Nacho Monreal.
Sotirios Papagiannopoulos turned the ball into his own net from Henrikh Mkhitaryan’s cross to make it 2-0 on 24 minutes.
Mesut Ozil got into the goal scoring act as he scored in the 58th minute to extend Arsenal’s lead to 3-0.
Seven-time UEFA Champions League winners, AC Milan, also recorded a convincing first-leg win as they thrashed Bulgarian club Ludogorets 3-0.
Patrick Cutrone broke the deadlock on the stroke of half-time for Milan.
Milan were awarded a penalty on 64 minutes which Ricardo Rodriguez converted.
And in the 90th minute, Fabio Borini put the game beyond doubt by adding the third goal for his side.
Former Manchester City and AC Milan star, Mario Balotelli, scored a brace but it was not enough as 10-man Nice threw away a 2-0 lead to lose 3-2 at home to Lokomotiv Moscow.
Balotelli opened scoring in the fourth minute to make it 1-0 to Nice.
Balotelli doubled Nice’s lead by converting a 28th minute penalty.
In the 45th minute, Lokomotiv Moscow pulled a goal back thanks to Manuel Fernandes who scored from the penalty spot.
Nice were reduced to 10 men following Racine Coly’s sending off in the 67th minute.
Lokomotiv took advantage of the sending as Fernandes restored parity for Lokomotiv by grabbing his second of the night to make it 2-2
Fernandes completed his hat-trick as he once again got on the score sheet to give his side a 3-2 lead.
Chelsea on-loan striker Michy Batshuayi continued his impressive goal scoring form for Borussia Dortmund who pipped visitors Atalanta 3-2.
Dortmund got the breakthrough from former Chelsea forward Andre Schurrle in the 31st minute.
Josip Ilicic struck back for Atalanta in the 51st minute and scored again on 59 minutes.
Batshuayi made it 2-2 for Dortmund on 65 minutes before netting the winner in the 90th minute to give Dortmund a slim first-leg win.
In other first-leg ties, Athletic Bilbao defeated Spartak Moscow 3-1 away, Real Sociedad were held to a 2-2 home draw by Salzburg while Marseille spanked visiting Sporting Braga 3-0.
In the day’s early kick-off, Portuguese club Sporting Lisbon defeated Kazakhstan side FC Astana 3-1 away in their first-leg encounter.
UEFA Europa League Round 32 1st-leg results:
Oestersunds 0 vs 3 Arsenal
Dortmund 3 vs 2 Atalanta
Ludogorets 0 vs 3 AC Milan
Nice 2 vs 3 Lokomotiv Moscow
Real Sociedad 2 vs 2 Salzburg
Spartak Moscow 1 vs 3 Athletic Bilbao
Marseille 3 vs 0 Sporting Braga