Arsenal will compete in the Champions League for the 14th consecutive season after their beleaguered side came from behind to record a brave 2-1 win at Udinese.
Leading 1-0 from the first leg of the play-off tie, Arsenal were menaced throughout by the threat of an elimination that would have been unthinkable in both sporting and financial terms.
In the 39th minute, Udinese's irrepressible talisman Antonio di Natale guided a header inside the right-hand post that levelled the tie on aggregate and took the Italians to within a goal of the group phase.
Arsenal captain Robin van Persie equalised 10 minutes into the second half, but the hosts were handed a chance to re-establish their advantage shortly afterwards when referee Olegario Benquerenca awarded a penalty against Thomas Vermaelen for handball.
Wojciech Szczesny excelled himself in the face of Di Natale's spot-kick, however, plunging to his right and somehow palming the ball over the crossbar despite the power and precision behind the Italian's rising shot.
The shock of spurning such an opportunity drew the hosts' sting and Theo Walcott put Arsenal out of sight in the 69th minute by racing into the box and coolly beating goalkeeper Samir Handanovic at his near post.
"We showed that, under pressure, we can respond with football and remain calm and composed on the ball and play like we know how to play," Arsenal coach Arsene Wenger told ITV.
"There are many questions around our club. If we'd gone out tonight it would have been worse for the team to play in a serene way.
"It was important tonight. Not financially, as some people have said, but more because we want to play at the top level."
On the day that Samir Nasri completed his move from Arsenal to Manchester City -- and just nine days after Cesc Fabregas returned to Barcelona -- it was a timely victory for Wenger, whose methods had been called into question with greater zeal than ever before as his squad collapsed around him.
His starting line-up contained five players aged 21 or under and two 19-year-old Champions League debutants in the shape of right-back Carl Jenkinson and holding midfielder Emmanuel Frimpong.
Frimpong was replaced by Tomas Rosicky at half-time but this remained a stirring performance by a young team scarred by the trauma of recent departures and bereft of Jack Wilshere, Laurent Koscielny, Kieran Gibbs, Abou Diaby and Nicklas Bendtner due to injury.
Amid stifling summer heat at Udine's Stadio Friuli, Arsenal began the game with a poise that seemed at odds with both the importance of the occasion and the doubt that is supposed to have overcome their ranks.
But if the visitors' start to the game was typical Arsenal, so was the failure to convert the chances that their slick football occasionally yielded, with Walcott the chief culprit in the 32nd minute.
After first Pablo Armero and then Di Natale had hit the woodwork for Udinese, Walcott could only find Handanovic's gloves after being picked out 10 yards from goal by the impressive Gervinho.
Di Natale's delicately lofted header, from Giampiero Pinzi's dinked pass, suggested Walcott's profligacy would indeed be punished.
Gervinho slipped past Mehdi Benatia to put the equaliser on a plate for van Persie, however, and Walcott's confident finish 14 minutes later stole the wind from the hosts' sails with the ruthlessness of a slashing dagger.
Their lead restored, Arsenal slipped back into trademark ball retention mode and had only a booking for Walcott that rules him out of their next match to rue as they eased into the familiar territory of the group stage.
"We have to accept that we were eliminated by a better team," said Udinese coach Francesco Guidolin, whose side will now enter the Europa League.
"We held our own against a great team and we're going out with our heads high."