Schalke manager Felix Magath believes going a goal down was the spark his side needed to progress to the Champions League quarter-finals.After the first-leg between Schalke and Valencia ended at 1-1 at the Mestalla, the La Liga side took an early lead and scored a vital away goal through Ricardo Costa after just 17 minutes.But that goal opened the game up and with Peruvian playmaker Jefferson Farfan dominating in midfield and scoring a double as Schalke came from behind to record a 3-1 win that sent them into the last eight of Europe’s most prestigious club competition for the second time in four years.”I think at the beginning the result from the first leg was a burden for us,” Magath said.”We were not aggressive enough, that’s why Valencia could raise their game. After we conceded it got better as we had nothing to lose anymore.””Then we fought back, but the situation was quite dicey and I would have liked Jefferson (Farfan) to score the (third) goal earlier.””We had Manuel Neuer and a bit of luck, but that’s what you need in order to reach the next round.”Valencia had several golden opportunities to equalise at 2-1 down, and coach Unai Emery insisted his side had thrown away a terrific chance to progress.”It’s so disappointing. With everything in our favour we managed to throw it all away,” Emery said.”At 0-1 we had the game under control with chances to counterattack, and then they go and equalise.””In the second half, without hardly creating a chance, they go 2-1 up. We then have four chances and don’t take any of them. We’ve lost unjustly.”Emery admitted he could not speak to his players after the game such was his disappointment, while he reserve praised for Neuer who made a string of excellent saves.”I went back into the dressing room so down that I couldn’t say anything to the players, but in reality I can’t hold them responsible for anything,” he said.”I must also recognise the great performance their goalkeeper (Manuel Neuer) put in. We can’t talk of bad luck tonight; we needed to be assertive and we weren’t.”