Arsenal were denied a fourth straight Europa League win as Vitoria Guimaraes earned a late 1-1 draw after a frantic finish in the driving ran in Portugal.
Shkodran Mustafi headed Arsenal into an 80th-minute lead, and they looked untroubled until a late flurry brought an acrobatic Bruno Duarte equaliser and almost a late winners as the hosts piled on the pressure.
It was the only shot on target Arsenal could muster throughout the game as, apart from hitting the post, they couldn't make the most of the possession they enjoyed.
Unai Emery made Rob Holding captain in the wake of the Granit Xhaka saga, but there was no end of the Gunners' misery as, despite being largely comfortable, they suffered a huge late wobble and looked anything but assured.
The draw was not enough to stop Vitoria from exiting the Europa League, and although it also meant Arsenal did not qualify immediately, they're inevitable progress will be confirmed if Eintracht Frankfurt beat Standard Liege on Thursday.
It's as easy as a cross & a head for Arsenal to go in front in Portugal #EuropaLeague #VITARS pic.twitter.com/lgmqv9ULkU
— Sporting Life Football (@SportingLifeFC) November 6, 2019
Arsenal enjoyed plenty of possession in the first half, tallying 65 percent in the first 45 minutes but only going really close when Nicolas Pepe struck a post after just eight minutes.
Vitoria made the most of their time with the ball as they looked dangerous on the break, with Emi Martinez forced into action when Lucas Evangelista fired in an effort from the edge of the area which the goalkeeper did well to palm wide.
Vitoria continued to hit Arsenal on the counter and forced Martinez into another save in the 19th minute, this time from a set-piece.
Edmond Tapsoba was left unmarked as he rose highest to an Evangelista free-kick but was denied by the Argentinian goalkeeper.
🤦‍♂️ The Gunners just cannot defend a lead can they!#EuropaLeague #VITARSpic.twitter.com/9qJYLB97vS
— Sporting Life Football (@SportingLifeFC) November 6, 2019
Both sides struggled to created chances in the second half, with Mustafi's header over the crossbar proving to be the only effort of note heading into the final 15 minutes of the match.
The breakthrough came with ten minutes left to play, when Mustafi was somehow left completely unmarked to power home his free header from Pepe's cross.
Arsenal looked comfortable right until the closing moments, when substitute Leo Bonatini, on loan from Wolves, blazed over the bar from 12 yards when unmarked.
The equaliser did come in the first of five added on minutes, when former Spurs man Marcus Edwards got a ball in down the right, which eventually fell to Duarte who produced an overhead kick which bounced into the far corner.
It could have been even worse for Arsenal right before the end when Mustafi almost put the ball through his own net, but Emery's men held out for a draw.