Mamer pulled off a significant upset by defeating title-chasing F91 Dudelange 1-3 away from home in the Luxembourg National Division on February 22, 2026. The visitors produced a stunning counter-attacking performance to stun one of the league's traditional powerhouses. Against the run of play, Mamer took the lead with a breakaway goal, and they doubled their advantage before halftime from a corner. Dudelange pulled a goal back early in the second half to set up a tense finish, but Mamer sealed the memorable victory with a third goal in stoppage time on another rapid break. This result throws the title race wide open and marks a historic win for Mamer, while Dudelange's championship hopes suffer a major blow.