FC Schalke 3 Valencia 1 (agg 4-2):Jefferson Farfan struck twice as Schalke fought back from an early deficit to progress through to the quarter-finals of the Champions League at the expense of Valencia.

Valencia, having drawn the first leg 1-1 at home, needed just 17 minutes to cancel out Schalke's away goal when Ricardo Costa headed them in front at the Arena AufSchalke, but the home side turned things around with two goals either side of half-time.

Farfan drew the hosts level with a brilliant 25-yard free-kick in the 40th minute before Mario Gavranovic netted seven minutes into the second half with an effort that sneaked in after hitting both posts.

Then, after Valencia had missed a number of chances to get back into the game and Gavranovic had hit the woodwork twice more, Schalke sealed the victory and their qualification when Farfan netted their third deep into injury-time.

Schalke came into the game in disappointing form and with question marks over the long-term future of coach Felix Magath, and the Gelsenkirchen outfit's fans must have feared things would get even worse as Valencia started well.

In the eighth minute Los Che defender Jeremy Mathieu saw a shot deflected just wide, and then nine minutes later the visitors got themselves in front.

Mehmet Topal did well down the left before firing in a fiercely-struck cross that Costa did well to head past Manuel Neuer at his near post.

Schalke striker Raul had a chance to cancel that goal out almost immediately but he headed wide, and soon after that Valencia almost made it 2-0 but Christoph Metzelder did well to block Aritz Aduriz's effort.

The Royal Blues looked set to go into the break still trailing but, with five minutes to go, they were handed a chance to draw level when they won a free-kick just outside the area.

It was a dangerous position, and Farfan made the most of it as he curled a superb free-kick into the top corner past Vicente Guaita, who got a fingertip to the ball but could not keep it out.

That was a huge boost for Schalke going into the interval, and it got better at the start of the second half as they took the lead.

Guaita could only push a cross down to Farfan inside the area, and although the Valencia goalkeeper managed to save the Schalke goalscorer's resulting shot, the ball fell perfectly for Gavranovic, whose effort hit the inside of the near post, rolled across the line and hit the far post as well before going in.

That goal set Schalke on their way to the last eight, but they had to survive some nervy moments before the end.

Within four minutes of Gavranovic's goal Aduriz had two great chances to score, but he fired his first into the side netting with Neuer out of position and then, after being put clean through, he was denied by a brilliant save by the Schalke goalkeeper and captain.

Tino Costa then missed another good opening for Valencia while Neuer was called into action again to save a Juan Mata shot.

Valencia could not force an equaliser though, and Schalke twice came close to killing the game off late on when Gavranovic hit the woodwork on separate occasions.

The first saw his thunderous drive deflected onto the near post by Guaita, and he then saw a brilliant 35-yard lob hit the Valencia crossbar with Guaita struggling.

Schalke were celebrating a third goal late on though as Farfan broke away before dinking the ball over Guaita to settle the contest.