(CNN) -

Football clubs spend big money on big players to deliver on the biggest stage.

And no doubt Arsenal view the $58 million they spent on Alexis Sanchez as a bargain after his heroics secured its passage to yet another European Champions League group stage.

Remarkably, a nervy 1-0 victory over Turkish side Besiktas in the two-legged playoff tie means Arsene Wenger's men will take their place in the draw for the 17th consecutive season.

Qualification also brings with it a $33 million windfall, meaning Sanchez has already paid off a large chunk of the fee it cost the club to prise him from Spanish giants Barcelona.

Now the Gunners will line up alongside the cream of Europe, including European champions Real Madrid and German champions Bayern Munich, in Thursday's draw.

A relieved Wenger told Sky Sports: "We needed to keep our nerve but we kept our nerve, were united and showed great solidarity.

"We wanted to be there and not go down a division in Europe. We had chances to score more but in two games we kept a clean sheet and it made a difference."

Asked if it was unthinkable for Arsenal not to qualify Wenger said: "It is unthinkable until it happens.

"For us it is a weight off our shoulders, we can now focus on the Premier League and wait for the draw. We feel we have done the job and have our conscience clear."

Wenger also confirmed striker Olivier Giroud would be missing until at least December after undergoing surgery on an ankle injury, and said he would dip into the transfer market if he could find a forward of suitable quality.

After a disappointing 0-0 draw in Turkey last week, the first opportunity of the evening fell to Jack Wilshere, but after pouncing on a loose ball when Sanchez was fouled, the England star fired wide of the target.

Former Chelsea striker Demba Ba, who wasted several opportunities in the first leg, narrowly failed to poke the ball past Arsenal goalkeeper Wojciech Szczesny as the Turkish side showed they could still pose an offensive threat.

And hearts were in mouths at the Emirates when defender Mathieu Debuchy slid in to tackle Mustafa Pektemek and appeared to get only a marginal touch on the ball inside the penalty area.

But just as the home fans began to express their agitation, Sanchez found the net.

The Chilean scampered into the area as Wilshere swapped passes with German World Cup winner Mesut Ozil, to fire low past Besiktas goalkeeper Tolga Zengin.

Sanchez had a chance to double Arsenal's lead on 51 minutes after more neat approach play from Wilshere, the 22-year-old sliding the ball to his Chilean teammate only to see it stabbed wide of the far post.

Ba had another chance to stall the Gunners' momentum as he turned inside the area, but his shot from a narrow angle could only find the side-netting.

Arsenal then wasted two glorious chances to make the tie safe.

With Besiktas pushing men forward, Arsenal broke and Sanchez drove into the penalty area before teeing up Cazorla, but the Spaniard's shot was blocked.

Seconds later Nacho Monreal swung in a low cross and though Alex Oxlade-Chamberlain sneaked in front of his marker, he could only fire against Tolga from six yards out.

A nervy climax was ensured when Debuchy was dismissed for a second bookable offense with 15 minutes left, the defender remonstrating with the referee before trudging off.

Ba failed to connect with a late header, and Arsenal were penned in as the Turks desperately sought the goal they needed, but they held on to seal victory.

Elsewhere, Spanish side Athletic Bilbao came from behind to eliminate Napoli, from Italy, and take its place in the European Champions League group stages for the first time in 16 years.

Germany's Bayer Leverkusen also progressed after a 7-2 aggregate victory over Danish outfit FC Copenhagen.