He narrowly took the first set 6-7(2), before going down 7-5 6-4 in the next two.
Belgian David Goffin won over three sets, beating Tunisia's Malek Jaziri 4-6 7-6(4) 6-2.
There was also a straight-sets win for Stefanos Tsitsipas of Greece, who won 7-6(3) 6-4 against Portugal's Joao Domingues.
In the evening's final match, Pablo Cuevas won 6-0 6-7(5) 6-2 against Frances Tiafoe of America.
Germany's Alexander Zverev was eliminated from the BMW Open in Munich after his quarter-final defeat to Chilean Cristian Garin. He lost 6-4 5-7 7-5.
His compatriot Philipp Kohlschreiber fared better, winning 4-6 7-5 6-4 over Matteo Berrettini of Italy.
Spain's Roberto Bautista Agut won 4-6 6-4 6-0 gainst Argentinian Guido Pella.
Italian Marco Cecchinato also won, recovering from losing the first set to beat Hungary's Marton Fucsovics 1-6 7-5 7-5.