Novak Djokovic exited the ATP 500 tournament in Basel in the second round following a three-set defeat against Germany's Jan-Lennard Struff.
Struff secured a 6-7, 7-5, 7-6 victory in a 2-hour 35-minute match, marking his first career win against the 24-time Grand Slam champion.
The defeat cost the seventh-ranked Serb crucial ranking points in his race to qualify for the ATP Finals in Turin.