Basel has suffered its ninth defeat this season in the Swiss Super League.
The Swiss champion lost 3:0 away on Sunday to St. Gallen, in the 29th round of the Swiss football elite.
Basel missed Xherdan Shaqiri due to injury, while Albian Ajeti and Dion Kacuri played from the 58th minute.
The home team scored the winning goals in the first half. Chima Okoroji scored the first goals, in the ninth and 15th minutes, while Carlo Boukhalfa scored the third goal in the 29th minute.
St. Gallen is in second place with 54 points. From 29 matches, Basel is in fourth place with 36 points.