Croatia beat Montenegro 7-5 to win a place in the gold medal match of the Olympic men's water polo, meaning the country will feature on the podium for the first time in the tournament since 1996.
The Montenegrins scored the first goal but struggled to penetrate the combination of Croatia's tight defence and their top-ranked goalkeeper in the middle periods of the game.
Croatia them imposed themselves to reach Sunday's final where they will face either Italy or Serbia, who meet in the other semi-final later on Friday.
Montenegro, which split from Serbia in 2006, was guaranteed its first Olympic medal on Thursday when its women's handball team qualified for the final.
The men's water polo team still have a shot at winning a bronze medal.
Italy defeated defending Olympic champions Hungary to progress to the semis.