Arsenal came from behind to beat Cologne in their delayed Europa League opener against a backdrop of crowd trouble at the Emirates Stadium.
Kickoff was delayed by an hour as ticketless away supporters attempted to enter the ground, with plenty of Cologne fans sat in among the home section when the tie finally got under way, with the Gunners eventually winning 3-1.
Four arrests were made on suspicion of public order offences as extra police were deployed to the scene.
On the pitch, Arsene Wenger’s much-changed side showed determination to fight back from Jhon Cordoba’s early 40-yard strike and seal three points.
It was only after the interval, following the introduction of Sead Kolasinac and a change of shape, that the Gunners hit back.
Kolasinac levelled less than four minutes after coming off the bench and Alexis Sanchez, a surprise starter ahead of a trip to Chelsea on Sunday, scored a marvellous solo goal before Hector Bellerin secured the win late on.
Everton were taught a lesson by Atalanta as they crashed to a 3-0 defeat in their group-stage opener.
Atalanta opened the scoring in the 27th minute, with Everton failing to deal with a corner and Andrea Masiello firing home the loose ball.
The Serie A side made it two in the 41st minute as Alejandro Gomez bent a fine strike into the far corner, before Bryan Cristante added a third on the stroke of half-time as he slotted past Maarten Stekelenburg.
Also in Group E, Sardinero Adrian scored a last-minute equaliser as Apollon Limassol secured a 1-1 draw against Lyon.
Memphis Depay broke the deadlock for Lyon, slotting home a penalty in the 53rd minute, but Adrian popped up deep into injury time to claim a point for the Cypriot side.
Andre Silva scored a hat trick as AC Milan eased to a 5-1 victory over Austria Vienna.
Milan came firing out of the traps with two goals inside the first 10 minutes as Hakan Calhanoglu rifled a strike into the top corner, before Andre Silva slotted home Calhanoglu’s pass.
Silva added a third on 20 minutes after linking up with Calhanoglu again before Vienna pulled one back just after the restart through Alexandar Borkovic’s header.
But Silva restored Milan’s three-goal advantage when completing his hat trick in the 56th minute and Suso then made it five in the 63rd minute with a long-range strike.
Elsewhere in Group D, AEK Athens edged Rijeka with a 2-1 victory as Lazaros Christodoulopoulos scored the deciding goal.
Nice stormed to a 5-1 Group K win at Zulte-Waregem with two goals from Alassane Plea and one each for Dante, Allan Saint-Maximin and Mario Balotelli, while Aaron Leya replied for the Belgians.
Also in Group K, Lazio twice came from behind to edge past Vitesse in Arnhem, Marco Parolo cancelling out Tim Matavz’s early strike and after Brian Linssen put the hosts back in front, Ciro Immobile and Alessandro Murgia won it in the last 23 minutes.
Ostersunds‘ remarkable Europa League run showed no signs of stopping as they opened their account in Group J with a 2-0 win over Ukrainian side Zorya in Lviv.
Second-half goals from Saman Ghoddos and Abdullhi Gero got the Swedish minnows, who have already beaten PAOK and Galatasaray in the competition, off to a flying start.
Also in Group J, Athletic Bilbao were held to a goalless draw by Hertha Berlin in the German city.
In Belgrade, Red Star Belgrade and BATE Borisov drew 1-1, Nemanja Radonjic opening the scoring for the home side and Nikolay Signevich equalising in their Group H clash.
Adil Rami scored the only goal as Marseille beat Konyaspor 1-0 in Group I, while Vitoria Guimaraes drew 1-1 with Salzburg, Pedrao’s opener cancelled out by Valon Berisha on the stroke of half time.
Vardar were no match for Zenit in Skopje, the Russians running out 5-0 winners in their Group L clash with two goals from Aleksandr Kokorin and one each from Branislav Ivanovic, Artem Dzyuba and Emiliano Rigoni.
Real Sociedad were the other big winners in Group L, though, beating Rosenborg 4-0 with two from Diego Llorente and further goals from David Zurutuza and a Jorgen Skjelvik own goal.
In Group A, Villarreal secured a 3-1 win over Astana.
The Spanish side edged ahead inside the 16th minute through Nicola Sansone, only for Yuriy Logvinenko to equalise in the 68th minute, before Cedric Bakambu and Denis Cheryshev both scored inside two minutes to swing the game back to Villarreal.
In the same group, Tomas Necid scored for Slavia Prague as they defeated Maccabi Tel-Aviv 1-0.
Braga came from behind to beat Hoffenheim 2-1 in Group C.
Wagner opened the scoring for Hoffenheim, heading home Pavel Kaderabek’s cross, only for Joao Teixeira to level the score just before the half-time whistle with a header of his own and Dyego Sousa to turn the game around with a strike in the second half.
Steaua Bucharest made a promising start in Group G with Constantin Budescu scoring twice and Denis Alibec getting the third in a 3-0 home win over Viktoria Plzen, while in the same group Hapoel Be’er Sheva beat Lugano 2-1, Dan Einbinder and a Sher Tzedek penalty enough despite a late Tzedek own goal.
Istanbul Basaksehir, meanwhile, played out a goalless draw with Ludogorets Razgrad.
In Group B, Young Boys drew 1-1 with Partizan Belgrade, while Dynamo Kiev dismissed Skenderbeu Korce 3-1.
And in Group F, Copenhagen drew 0-0 with Lokomotiv Moscow, with Zlin doing the same against Sheriff Tiraspol.
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