كتب : Omar Shoeb
Daniel Borimirov gave Levski the lead early in the fifth minute before Schalke retaliated with three goals by Gustavo Varela, Lincoln and Gerald Asamoah in the second half.
Swiss side Basel also beat Premiership club Middlesbrough, who forced Italian giants AS Roma to exit the UEFA Cup from the round-of-16, 2-0 thanks to Matias Delgado and David Degen strikes before the interval.
Meanwhile, Rapid Bucharest were held by city-rivals Steaua Bucharest to a 1-1 draw that is expected to keep things heated for the second-leg.
Also, Argentine star Javier Saviola netted a brace to lead Spanish outfit Sevilla to a 4-1 victory over Russian club Zenit St. Petersburg.
Jose Luis Marti added another goal for Sevilla from a spot-kick, and Claro Adriano Correia sealed their victory in the 93rd minute, while Alexander Kerzhakov scored Zenit’s only goal.