The top-seeded Cilic will be seeking his third Zagreb title Sunday when he battles No. 4 seed Austrian Jurgen Melzer in the finals.
Cilic, who won the tournament in 2009 and 2010, knocked off No 3 seed Youzhny 4-6, 6-4, 6-3.
Melzer advanced with a 7-6 (7-2), 6-3 win over Robin Haase of the Netherlands.
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