From 2011 to 2017, Arsenal lost at least one game in of their two-legged ties in the first knockout round of the Champions League: three times to Bayern Munich, and once each to AC Milan, Monaco and Barcelona.
Those defeats contributed greatly to the club's European stagnation, which has seen the Gunners not get beyond the Round of 16 since a quarterfinal appearance in 2010, when Arsenal were eliminated by Barcelona.
This season, almost as if it's ingrained in the DNA, they flopped at the Emirates again by losing 2-1 to Swedish minnows Östersunds FK. At least the difference this time was that the 3-0 lead Arsenal took from the first leg, plus a Sead Kolasinac goal on Thursday, saw them qualify on aggregate for the next round, in which they will renew acquaintances with Milan.
It was a worrying night for Arsene Wenger who, despite saying his team had "prepared properly and in a serious way," also admitted there was a lot missing from the performance.
"We were complacent, not focused and were open every time we lost the ball," he said. "People subconsciously think you just have to turn up to win the game."
Serious and proper preparation means your players don't perform in that way and, while Arsenal always looked to have just that bit extra than their opponents, it tells us that there's either something wrong with Wenger's pre-match planning and motivation, or that his messages are not getting through to -- or being ignored -- by his players.
It was a game that was supposed to give fringe members of the squad a chance to show they can force their way into the reckoning for "first team" games, yet the fact that nobody did that adds another layer of disappointment to it.
Danny Welbeck, for example, must have looked at a tie against a side in the midst of preseason preparations and fancied his chances of a confidence-boosting goal or two. Instead, two more games without scoring and he continues to look a long way off his best.
Instead of creating a competitive environment in which second-string players can play regularly and push for Premier League action, the Europa League has divided the squad almost neatly in two. There's the weekend crew -- the big names and the stars who play in league games -- and the rest.
There's some crossover, but only Jack Wilshere and Ainsley Maitland-Niles have made the step up. Even then they're hardly first choices and it appears as if the two-tier system has been far from the motivational tool that Wenger might have hoped it would be.
What's also clear is that, as the competition heats up, Wenger has to start picking stronger teams. Milan are a long way from the fearsome Rossoneri sides of the past, but Arsenal also are some distance from where they used to be.
The defeat on Thursday, on top of a group-stage loss to Cologne, highlights the limitations of the Gunners' second string. If they can't do it at home against a team like Östersunds, then it's a big stretch to think they can go to the San Siro and be competitive.
With qualification for the Champions League via the Premier League top four looking increasingly unlikely, the path to next season's European top table lies with the Europa League. There are basically two prizes for winning it. The first is an actual trophy -- and it would become only the third continental triumph in the club's history -- and the second is Champions League football in the next campaign.
While Wenger has to at least try and keep his team motivated in the league, he must put more and more of his eggs in the Europa League basket and hope that stronger team selection will improve performances accordingly.