In a game marked by rough and aggressive play in front of both goals, Serbia showed superior firepower and defence.
Serbia's Dusan Mandic scored four times, while goalkeeper Branislav Mitrovic's impressive blocks kept Croatia out.
Rio 2016
U.S women win water polo gold to defend Olympic title over Italy
19/08/2016 AT 20:51
A Serbia team that has swept up world and regional titles since 2012 finally proved its dominance on the most prestigious stage after taking bronze at the last two Games.
Serbia began the tournament with two draws and a loss, but steadied their performances in the later rounds with five straight wins on their way to the title.
Rio 2016
'Argh, my eyes!': Rio chiefs turn water polo pool blue again... but end up stining athletes' eyes
11/08/2016 AT 13:38
Rio 2016
Masked man powers Italy to water polo win over France
08/08/2016 AT 17:22