Super League leaders Young Boys had their advantage cut to four points after suffering a resounding 4-0 defeat at nearest challengers Basle. The home side had to wait until the 69th minute for the opening goal, with Alexander Frei scoring from the penalty spot.
But that opened the floodgates with Marco Streller doubling the lead nine minutes from time before Marcos Gelabert and Berang Safari added late goals.
Aarau come to life
In a high-scoring day in the Swiss top flight, Aarau gave their best display of the campaign to beat Bellinzona 6-3 in a relegation dogfight.
Aarau had only won once and scored 11 times heading into the match, but in an impressive display they shared the goals around between Giuseppe Aquaro, Martin Stoll, Patrick Bengondo, Steven Lang, Sergio Jose Bastida and Orhan Mustafi.
Mark Edusei, Ildefons Lima and Alessandro Ciarrocchi were on target for Bellinzona, who had their advantage over the basement side trimmed to five points.