Arsenal have failed to win their past two games after a run of eight straight wins in all competitionsPremier League leaders Arsenal missed a chance to seal top spot in Europa League Group A as they lost to PSV Eindhoven in the Netherlands.
The Gunners only needed a point to go straight through to the last 16 next March.
But Joey Veerman's first-time finish from 16 yards and a header by substitute Luuk de Jong - after a mistake by keeper Aaron Ramsdale on his European debut - saw Mikel Arteta's side lose in Europe for the first time this season.
PSV, managed by former Manchester United forward Ruud van Nistelrooy, also had three goals ruled out for offside as Arsenal were well beaten.
The Gunners need to beat Zurich in their final group game next Thursday at Emirates Stadium (20:00 GMT) to guarantee a place in the last 16.
If they fail to win and PSV beat Bodo/Glimt in Norway, Arsenal will face two extra games in the knockout round playoffs, where teams that finish third in the Champions League group stage, including Barcelona, drop into.
Arsenal suffered just their second ever away defeat in the group stages of the Europa League and first since November 2017Gunners fail biggest Euro test to date
Arsenal had been pretty much faultless in Europe this season after four wins out of four, including a narrow 1-0 win over PSV at Emirates Stadium last week.
This was their biggest test to date, yet they were second best as PSV - who included Jarrad Branthwaite, on loan from Everton, in the centre of defence - produced a dominant performance in front of their own fans.
Cody Gakpo and 19-year-old former Paris St-Germain midfielder Xavi Simons caused the Gunners defence all sorts of problems. Gakpo had two goals ruled out for offside and Simons one.
Arsenal were living dangerously and it was no surprise when Veerman swept the hosts ahead before De Jong struck after Ramsdale failed to connect while trying to clear a corner.
While Arsenal host Zurich on 3 November, PSV Eindhoven are in Norway to face Bodo/GlimtBy the end, Arsenal finished with substitutes Gabriel Jesus, Bukayo Saka and Thomas Partey on the pitch but they were unable to rescue a point.
Having won eight successive games in all competitions, Arteta's side have now failed to win their last two.
They remain favourites to finish top of the group, but Arteta now seems unlikely to be in a position to rest key players before the heavyweight London derby at Chelsea on 6 November after a second defeat in 16 games this season.
Player of the match
de JongLuuk de Jong
PSV Eindhoven
Squad number9Player namede Jong
Squad number22Player nameBranthwaite
Squad number11Player nameGakpo
Squad number7Player nameSimons
Squad number23Player nameVeerman
Squad number10Player nameMadueke
Squad number17Player nameMauro Júnior
Squad number6Player nameSangaré
Squad number5Player nameAndré Ramalho
Squad number31Player nameMax
Squad number21Player nameEl Ghazi
Squad number3Player nameTeze
Squad number29Player nameMwene
Squad number1Player nameBenítez
Squad number15Player nameGutiérrez
Squad number20Player nameTil
Line-ups
PSV Eindhoven
Formation 4-2-3-1
1Benítez
29Mwene5Ramalho Silva22Branthwaite31Max
6Sangaré15Gutiérrez
21El Ghazi23Veerman11Gakpo
7Simons
1Benítez29MweneBooked at 68mins5Ramalho Silva22BranthwaiteSubstituted forTezeat 81'minutes31Max6Sangaré15Gutiérrez21El GhaziSubstituted forde Jongat 45'minutes23VeermanSubstituted forTilat 81'minutes11GakpoSubstituted forMauro Júniorat 84'minutes7SimonsBooked at 80minsSubstituted forMaduekeat 80'minutesSubstitutes
2Hoever3Teze4Obispo8van Ginkel9de Jong10Madueke16Drommel17Mauro Júnior20Til24Waterman27Bakayoko37LedezmaArsenal
Formation 4-3-3
1Ramsdale
18Tomiyasu12Saliba16Holding3Tierney
8Ødegaard23Sambi Lokonga34Xhaka
21Fábio Vieira14Nketiah11Martinelli
1Ramsdale18TomiyasuSubstituted forWhiteat 74'minutes12Saliba16HoldingSubstituted forGabriel Jesusat 64'minutesBooked at 79mins3TierneyBooked at 58minsSubstituted forGabrielat 74'minutes8ØdegaardSubstituted forSakaat 57'minutes23Sambi LokongaSubstituted forParteyat 56'minutes34XhakaBooked at 80mins21Fábio Vieira14Nketiah11MartinelliBooked at 67minsSubstitutes
4White5Partey6Gabriel7Saka9Gabriel Jesus17Cédric Soares24Nelson31Hein44Cirjan72Smith89IbrahimLive Text
Match ends, PSV Eindhoven 2, Arsenal 0.
Second Half ends, PSV Eindhoven 2, Arsenal 0.
Gabriel Jesus (Arsenal) wins a free kick in the attacking half.
Foul by Érick Gutiérrez (PSV Eindhoven).
Corner, Arsenal. Conceded by Mauro Júnior.
Attempt blocked. Gabriel Magalhães (Arsenal) left footed shot from the centre of the box is blocked.
Corner, Arsenal. Conceded by André Ramalho.
Bukayo Saka (Arsenal) wins a free kick on the right wing.
Foul by Mauro Júnior (PSV Eindhoven).
Corner, PSV Eindhoven. Conceded by Gabriel Magalhães.
Foul by Gabriel Magalhães (Arsenal).
Luuk de Jong (PSV Eindhoven) wins a free kick on the right wing.
Bukayo Saka (Arsenal) wins a free kick in the attacking half.
Foul by Philipp Max (PSV Eindhoven).
Substitution, PSV Eindhoven. Mauro Júnior replaces Cody Gakpo.
Foul by Thomas Partey (Arsenal).
Guus Til (PSV Eindhoven) wins a free kick in the defensive half.
Substitution, PSV Eindhoven. Guus Til replaces Joey Veerman.
Substitution, PSV Eindhoven. Jordan Teze replaces Jarrad Branthwaite.
Granit Xhaka (Arsenal) is shown the yellow card.
