Udinese 1-2 Arsenal (agg 1-3)
Arsenal cast aside their recent troubles to reach the Champions League group stage with victory at Udinese in their qualifying play-off second leg.
The Gunners won the first leg 1-0 but Udinese went ahead in Italy through Antonio di Natale's superb header.
Robin Van Persie equalised from Gervinho's pass before Thomas Vermaelen handled a Di Natale corner in the box.
Wojciech Szczesny saved the penalty and Theo Walcott sealed a 2-1 win (3-1 on aggregate) with a fine run and finish.
It capped a critical win for Arsene Wenger's side and means they will be in Thursday's draw for the group stages as they prepare for a 14th consecutive season in the competition proper.
Their preparations were disrupted by Samir Nasri's move to Manchester City and news that Jack Wilshere was facing an extended spell on the sidelines.
Huge pressure had also built on the team and manager Arsene Wenger following their winless - and goalless - start to the Premier League season.
But Arsenal at least carried a one-goal advantage to north-east Italy and, despite the sweltering conditions at Stadio Friuli, they got off to an enterprising start.
Gervinho was released down the left and saw a low cross gathered by Samir Handanovic with Van Persie waiting to pounce, and moments later Walcott stung the goalkeeper's palms from about 20 yards.
Udinese were struggling to keep pace with their opponents' slick passing and movement but, as is often the case, Arsenal failed to make their superiority count and that encouraged the Italians to grow in confidence.
Di Natale crossed for Pablo Armero to bounce a header against the post, Di Natale was then denied by the same piece of woodwork with a low strike from a Mauricio Isla centre.
Handanovic produced a superb double save from Walcott and Van Persie, but at the other end Di Natale almost latched on to a deflected effort from a tight angle - and he made no mistake a few minutes later as the 33-year-old found himself completely unmarked to meet Giampiero Pinzi's dinked cross and steer his header past Szczesny.
Wenger opted for experience over youth at half-time - replacing Emmanuel Frimpong with Tomas Rosicky - and shortly after Alex Song failed to connect with a free header from a Van Persie set-piece, Arsenal were back on level terms.
Gervinho again surged in from the left, this time weaving past Medhi Benatia, and cut the ball back for Van Persie to shoot home from eight yards.
The Dutchman's strike appeared to deflate Udinese and their fans but they were gifted a route back into the tie when Vermaelen handled Di Natale's corner.
Unfortunately for the former Italy international, Szczesny dived to his right and pushed the spot-kick to safety with an outstanding one-handed effort.
That proved to be a pivotal moment, and it was not long before Walcott exchanged passes with Bacary Sagna, sprinted clear and slotted past Handanovic.
Di Natale drilled wide and watched on as a free-kick rebounded off the post, while Van Persie and substitute Armand Traore went close to extending Arsenal's lead.
The Gunners held firm and were left to breathe a huge sigh of relief.