World number one Novak Djokovic was brought to tears after he bowed out of his Adria Tour with victory over German Alexander Zverev in front of home fans.
The 4-0 1-4 4-2 win sent fellow Serb Filip Krajinovic into the final.
Djokovic's event - the first elite men's tennis since it was suspended by coronavirus - attracted 4,000 fans.
"I am just overwhelmed by emotion because this reminds me of my childhood," he said as the Belgrade crowd gave him a standing ovation.
"It's been an emotional few days and I want to thank everyone who made this possible.