The triumph marked the Norway defender's 100th appearance for Fulham.
"I didn't know that was my 100th appearance!" Hangeland told fulhamfc.com. "Well, it was a great way to celebrate it - the perfect, perfect way!
"To reach the Quarter-Final of a European competition is a dream come true for me - we've come really far and no one can take this away from us no matter what happens. It's great to be a Fulham player.
"It's probably the best feeling I've had as a Fulham player together with the final day of the 2007/08 season at Fratton Park - it was unbelievable and one for the record books.
"It seems like a long time ago but it's just over two years since I joined and to think how far we've come to be able to beat a top European side 4-1 at the Cottage - it's something we're all really proud to be part of."