Udinese 1 Arsenal 2 (Arsenal win 3-1 on aggregate): If this season for Arsenal turns out to exceed the expectations that many have for it, then Arsene Wenger may well look back in May to a tense, hot night in Italy nine months earlier and reflect that it was in Udine that his team's fortunes finally changed.
Arsenal have had a terrible 2011, only two wins in the Premier League since the end of February, two key players departed this summer and a rift developing between the club's famous manager and the fans.
Last night they did not just secure their Champions League lives for another season but they showed some of the grit and resolve that gives the embattled Wenger project more than just a glimmer of hope for the future.
Arsenal still have to go to Old Trafford on Sunday weighed down by suspensions and injuries to face the champions but at least today they will be in the draw for the Champions League group stages for the 15th consecutive year.
At times that looked in doubt, especially when Antonio Di Natale's goal levelled the tie in the first half.
That goal asked serious questions of Wenger's players — and the response they provided in the second half went a long way to allaying the fears that this is a club consumed by crisis.
They dragged themselves back into the game through Robin Van Persie's equaliser and they won the match with a magnificently taken winner by Theo Walcott.
Between those two goals came arguably the game's defining moment: a brilliant penalty save by Wojciech Szczesny that took the wind out of Udinese's sails when they might just have overrun Arsenal.
Of all the problems that have beset Wenger in recent years, it is fair to say that we can cross the goalkeeping conundrum off the list for the long-term.
Szczesny has looked impressive for a while but last night he was a matchwinner, stopping everything apart from Di Natale's looping header in the first half. That he did so behind a patched-up defence speaks volumes about the confidence of this young goalkeeper.
He was not the only one. After a shaky first half, Arsenal came good. Even though it was Thomas Vermaelen who conceded the penalty he was excellent in defence. Gervinho opened up Udinese for Van Persie's equaliser and by the end of the match the Arsenal fans were singing to Wenger to acknowledge them with a wave.
It was only midway through the first half that Uefa announced Trabzonspor would take the place of Fenerbahce in the Champions League, closing off one possible backdoor route to the group stages if Arsenal were to fail last night.
Di Natale hit the post in the 23rd minute. That was on 39 minutes when Giampiero Pinzi picked out Di Natale with a cross. He had drifted behind Johan Djourou and he placed his header over Szczesny and into the far left corner of the Arsenal goal via the post. He deserved it.
At half-time Wenger made a crucial change. In the place of Emmanuel Frimpong he brought on Tomas Rosicky, who added to their creativity.
Gervinho got past Medhi Benatia on the byline, picked out Van Persie and he beat Handanovic from close range.
The penalty save by Szczesny just before the hour was crucial. It was a dubious handball decision against Vermaelen but Szczesny turned the ball over the bar.
Within ten minutes Arsenal were out of sight.
Funny old player, Walcott. First half he could not score from seven yards, the second he buried the ball like the 25-goal a season striker.
On this occasion his pace took him clean away from Benatia and, running down the left flank, he deceived Handanovic by placing a right footed shot inside the goalkeeper's right post. It had been a monumental night for Arsenal; and a win they needed badly.