Only a few months ago the 26-year-old Peruvian, who has had a rollercoaster relationship with coach Felix Magath, was desperate to leave the club and was criticised by fans after arriving late for their winter training camp in Turkey.
After the attacking midfielder struck twice to send Schalke through with a 3-1 victory over Valencia on Wednesday, and a 4-2 win on aggregate, there were no whistles or jeers from fans who had previously branded him ungrateful and a mercenary.
"Two goals. That is very good but I am just happy the team is through, that is the most important thing," Farfan, who has also had his share of problems with the Peru national team from which he has been suspended in the past, told reporters.
"I hope I gave our fans something to smile about."
He certainly did when he first cancelled out Ricardo Costa's lead with a curled free-kick minutes before the break and with Schalke on the back foot for most of the first half.
His speed down the wing kept causing problems as the German team looked dangerous on the counter-attack.
Farfan, who joined Schalke in 2008, made sure of their fourth win in four home games in the competition this season when he chipped the ball over Valencia keeper Vicente Guaita to make it 3-1 in stoppage-time after a nervy final few minutes.
"I am proud with how my players outplayed a top quality national team," coach Magath said. "We showed we are better when we face top teams."
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