LONDON -- Three quick thoughts from the Emirates after Arsenal reach the round of 16 of the Europa League despite a 2-1 home loss to Ostersunds, going through 4-2 on aggregate.
1. Arsenal avoid a monumental fiasco
What was supposed to be a formality turned into a near-fiasco for Arsenal.
Minnows Ostersunds threatened to make this one of the most embarrassing evenings in Arsenal history as they struck twice in two first-half minutes before Sead Kolasinac steadied the ship with a thumping volley just after the break.
Arsenal held a seemingly comfortable 3-0 lead from the first leg but somehow managed to turn this into a nervy evening thanks to a first-half performance that was shockingly poor even in light of the many previous low-water marks this team has produced lately.
The tiny Swedish club, playing their first season in Europe, struck twice in two minutes as Hosam Aiesh forced an own goal from Rob Holding and Ken Sema finished off a clinical move in quick succession.
It produced a kind of "is this really happening" atmosphere at the Emirates, with the Arsenal players looking shell-shocked and failing to produce anything resembling a proper performance. Playing against a team from a town of 50,000 and with an annual budget of £5 million (before the influx of Europa League money), Arsenal didn't produce a single scoring chance in the opening 45 minutes.
One can only imagine what Arsene Wenger told his players at half-time, but whatever it was, it worked. Kolasinac made the entire Emirates draw a sigh of relief just minutes after the restart when the ball fell to him in the box and he calmly hammered home a strike with his right foot.
That settled the nerves for the Gunners, and suddenly David Ospina's penalty save toward the end of the first leg became hugely important, as Ostersunds would have needed two more goals to turn things around.
They came close to a third on a couple of occasions, with substitute Dino Islamovic turning one effort just wide of the post, but Arsenal held firm. Still, Ostersunds became just the second team to win at the Emirates this season -- joining Manchester United.
So while it is Arsenal who will march on, only the Swedish club will view this as a night to remember.
2. Arsenal's second string fails to impress... again
Arsene Wenger said before this game that Arsenal would be "absolutely stupid" to think they could cruise through this second leg. And yet all 11 players in blue -- as the away kit was used at home -- seemed to believe they could do just that.
The back four was caught completely out of position on numerous occasions, the midfield kept giving the ball away and Danny Welbeck offered little threat up front despite his energetic runs. There were a number of players with a point to prove here -- Welbeck, Ainsley Maitland-Niles, Kolasinac and Ospina among them -- but none of them impressed.
Kolasinac showed his scoring threat again, but also showed why Wenger has been reluctant to use him at left-back as he completely lost sight of Aiesh and allowed him to run clear on goal ahead of the opener.
Maitland-Niles got another start in central midfield but was hooked for Granit Xhaka at half-time after struggling to get involved in the attack or stabilise the defence. Welbeck looks excruciatingly short of confidence and botched a couple of good scoring chances in the second half. Ospina should have done better on the first goal but was repeatedly let down by his defence.
In all, this was a reminder that Wenger will have to field his strongest side going forward if he wants to get anywhere near the final in Lyon. Because this second string won't take him there.
3. Ostersunds show what they're all about
If anyone was still wondering, Ostersunds showed just how the small club with no European pedigree made it to this stage in the first place. After a timid start to the first leg in Sweden -- which ultimately cost them the tie -- they played like a team with nothing to lose at the Emirates. And like a team with no fear, respect or inferiority complex.
English coach Graham Potter reverted to his normal attack-minded football and it seemed to take Arsenal completely by surprise (even though no other tactic made sense for the visitors).
The Swedish team offered the first warning shot when attacking midfielder Brwa Nouri was played clear in the area, but he seemed surprised by the pass and couldn't control the ball. But they kept slicing Arsenal open, and their quick-fire two goals came from brilliant team moves.
Sema in particular was impressive. He had toyed with Hector Bellerin early on when breaking in from the right flank, and held off Calum Chambers easily before spinning and shooting past Ospina on his goal.
Kolasinac's goal seemed to take the air out of the visitors somewhat, but this still goes down as the most impressive result in a campaign that has included wins over Galatasaray, PAOK and Hertha Berlin.
And while this may have been a once-in-a-lifetime opportunity for Ostersunds, one wouldn't be surprised to see Potter back at the Emirates soon. Because if Premier League clubs hadn't already taken notice of the Englishman's success, they will have now.