In his final professional appearance, the 2002 UEFA Cup Final against Feyenoord, Kohler was sent off for a foul on Jon Dahl Tomasson in the 31st minute of the match. After losing possession to Tomasson on the edge of Dortmund's penalty area, Kohler tripped the Danish forward inside the area to concede a penalty kick and was given a straight red card by referee Vítor Melo Pereira. Pierre van Hooijdonk scored the opening goal from the resulting penalty and BVB went on to lose the match 3–2.