Pavic and 28-year-old Siegemund were better than their American opponents Coco Vandeweghe and Rajeev Ram, winning 6:4, 6:4.
Pavic and Siegemund reached the finals without dropping a single set and were impressive again against the 7th seeds in the final. Laura Siegemund is ranked 27th in the world in singles, while Pavic is a specialist doubles player on the tour claiming five titles with Kiwi Michael Venus.
The win at the US Open means it is the fifth time a Croatian player has claimed a Grand Slam title. The left-handed player from Split now joins Iva Majoli (French Open singles), Goran Ivanisevic (Wimbledon singles), Marin Cilic (US Open singles) and Ivan Dodig (French Open doubles) as winners at Grand Slam tournaments.