World number one Novak Djokovic is out of the Srpska Open thanks to a straight-set defeat by fellow Serb Dusan Lajovic in the quarter-finals.
Djokovic, 35, was beaten 6-4 7-6 (8-6) by the world number 70 in Bosnia-Herzegovina.
It is a further blow to Djokovic as he builds up to next month's French Open.
"I'm overwhelmed," said Lajovic. "It's the biggest win of my career. Beating him is something I didn't even think was possible, but it happened."
Djokovic, who suffered a shock defeat by Lorenzo Musetti at the Monte Carlo Masters last week, has been troubled by a right elbow problem.