Alexander Frei scored in each half to steer FC Basel 1893 to a comfortable win over PFC CSKA Sofia that sent the Swiss club to the top of Group E.
The deserved victory over a lacklustre CSKA left them on six points, one ahead of Fulham FC and two clear of AS Roma, while CSKA are five adrift. It also ended CSKA's unbeaten run of nine home games in European competition, dating back to a 1-0 defeat by Hamburger SV in October 2005.
Looking dangerous whenever they pushed forward, Basel took a 20th-minute lead when Marco Streller allowed a long ball to bounce past him for Frei to chest down and steer past the advancing Ivan Karadzhov. The Switzerland striker was a constant menace and could have had a second when he burst through in the 39th minute, leaving two defenders in his wake, but could only drill his shot wide of the post.
The hosts conjured up little at the other end, with their best chance falling to Marquinhos just before the break. Striker Yordan Todorov got behind the Swiss side's defence but his cutback was met by a first-time shot from the Brazilian midfielder which ballooned over the bar.
Basel kept up the momentum after the break and only a last-ditch tackle by substitute Aleksandar Branekov denied Frei just before the hour mark as he waited to pull the trigger with the ball dropping. Frei's second was simply being postponed, though, as he rose to meet Carlitos's cross from the right with a header in the 63rd minute. Karadzhov got the better of another Frei effort in a goalmouth melee but then rode his luck in the closing stages when Behrang Safari was teed up by replacement Federico Almerares but fired over.