Marcelo Bielsa's men managed to comeback twice from a goal down to secure a spot in the final four, dashing the hopes of the Germans who looked poised to comeback
After a 4-2 victory in Germany last week, Marcelo Bielsa's men managed to comeback from a goal down on two occasions to level the score and secure the tie, setting up a date with Portugal's Sporting Lisbon in the final four.
It took just 10 minutes for the visitors to create their first chance. A lobbed ball into the box found Klaas-Jan Huntelaar, who acrobatically volleyed it on to the crossbar, but Gorka Iraizoz managed to get a hand on it sending it over the goal.
Both teams managed to advance up the pitch in the ensuing minutes but failed to create quality threats until the German's star striker rebounded to fire home the first.
28 minutes in, Huntelaar gained possession of the ball on the edge of the box after a pass from Chinedu Obasi, before moving toward the centre and firing a low, right-footed effort into the lower-left of the net, beating the outstretched hand of the Athletic Bilbao goalkeeper.
Needing two more goals to take the lead in the tie, a free-kick from Huntelaar flew over the net from 30 yards just minutes later. The wasted chance would prove costly.
Ander Herrera was taken off with an injury half an hour in, with Ibai Gomez replacing him. The fresh face attacker managed to turn the tide just five minutes from the break after receiving the ball on the left wing. Gomez took a touch inside from distance before hitting a wonderful effort that curled past Lars Unnerstall, falling into the inside of the far post to make it 1-1.
Needing three more goals and none from the hosts to advance, Schalke failed to add another before the half-time whistle.
In the second period, the guests took the lead on the evening again with a delightful strike from the edge of the box. After receiving a ball from Obasi, Raul drilled a curling effort into the right side of the goal, which hit off the post, making it 2-1 and providing a bit of hope for his side.
Just moments later, Marcelo Bielsa's man killed Schalke's hopes of reaching the semi-finals by scoring the tenth goal in the tie. Markel Susaeta finished with a low effort from just outside the box into the right side of the goal after a through ball from Fernando Llorente.
Athletic adopted a defensive style in the closing stages of the game and although Schalke continued to fight to pull off an improbable comeback, the home side did enough to hold on and advance.
The Basque outfit will now play the semi-finals on April 19th and 26th against Sporting Lisbon, while Huub Stevens' men see their hope of European glory reach its end this season.