If Arsenal do crash out of the Europa League next week, then they will look back on this quarter-final first-leg draw with Slavia Prague and wonder what might have been.
Arsenal were not at their best - far from it - but they still carved the visitors open enough times to claim a handsome win.
In the end, they missed four great chances. Bukayo Saka squandered one in the first half and then after the break Alexandre Lacazette missed two more. Pierre-Emerick Aubameyang, who came off the bench, was culpable, too.
Nicolas Pepe was the only one with a cool head in the end, scoring a lovely dinked finish in the 86th minute.
That put Arsenal 1-0 up and suddenly, despite the missed chances, it felt like a result that was at least palatable.
Slavia, however, struck in the 93rd minute as Tomas Holes headed home to leave the Gunners with a bitter taste in their mouth.
They now have it all to do in the second leg, with Slavia knowing that a 0-0 draw in Prague would be enough to see them through to the semi-finals.
It is not an insurmountable task for Arsenal, but it is one they wouldn't be facing had they been more clinical.
That is something that has been lobbied at the Gunners all season, with Arteta himself confessing that his side isn't ruthless enough. On Thursday, that proved to be true and in the most painful fashion.
Their troubles in defence were highlighted as well. 1-0 was not a bad result and, with four minutes of normal time to go, you have to see it out. Arsenal didn't and now they have it all to do next week.
Late substitutes add to feeling of what might have been © Provided by Evening StandardArsenal FC via Getty Images
Arteta had five substitutes at his disposal on Thursday and yet it was not until the 73rd minute that he opted to roll the dice.
It felt too little, too late and the way Arsenal improved after the changes made you wonder if they could have been made earlier.
Gabriel Martinelli provided spark and energy out wide, certainly more than Willian did for 70 minutes, while Aubameyang and Pepe combined for the goal.
In tight games like this, it is always difficult to know whether to stick or twist - but it felt like Arteta stuck for too long.
The game was stretched and open, there for the taking, but Arsenal didn't oblige until too late.
Tierney absence shown by lopsided attack © Provided by Evening StandardGetty Images
We all knew Arsenal would miss Kieran Tierney, but this draw only reinforced the point. A team shouldn't be this reliant on a left-back, but Arsenal are.
Without Tierney, the attack just looks lopsided. Everything came down the right side and Saka, which is not a bad tactic given his talent, but the lack of another option and the ability to switch it didn't help.
Cedric Soares did his best to fill in, however he just cannot offer what Tierney does. Arteta said in his pre-match press conference that the Scot is basically irreplaceable - and we saw that on Thursday.