Marin Cilic became the first player from the country in 22 years to win the Croatia Open by beating Marcel Granollers of Spain 6-4, 6-2 in Sunday's final.
Cilic trailed 4-2 in the first set before winning nine games in a row to seize a commanding 5-0 lead in the second.
Cilic served for the match at 5-1, but Granollers broke and saved two match points before Cilic sealed the victory with a forehand winner.
Cilic is the first Croat to claim the title since Goran Prpic won the inaugural event in 1990. It was his second title of the year, after winning at Queen's Club last month.
"This was a special week and a special victory for me," Cilic told the crowd in Umag. "I played some great tennis."
Despite the loss, Granollers will crack the top 20 in the ATP rankings Monday for the first time, jumping from 24th to 19th. He won his last title in Valencia in November last year.