Marin Cilic has won his first Grand Slam title by crushing Kei Nishikori in straight sets in the US Open final.

The Croat served his way to a one-sided 6-3 6-3 6-3 victory in the first major final not involving Roger Federer, Rafael Nadal or Novak Djokovic since 2005.

Nishikori shocked Djokovic in the last four at Flushing Meadows and started brightly by earning a break point in the opening game, but that was as much trouble as Cilic had on serve throughout the first set.

The 14th seed conceded only one point in his next four service games, and broke Nishikori at the third attempt midway through the first on his way to going a set ahead in only 34 minutes.

Cilic mastered his big-serving game in windy conditions, but Nishikori continued to struggle and lost game three of the second, before wasting four break points in a crucial juncture of the set.

A exchange of three consecutive breaks at the end of the set also went the way of Federer's semi-final conquerer, and gave Cilic full command of an encounter between two Grand Slam final rookies.

Cilic was certainly coping with the pressure the better of the two players, and had established a two-set-and-3-1 lead by the time that he broke the Japanese for a fifth time midway through the third.

Nishikori, the first man from his country to reach a major final, briefly rallied in game seven but wasted his last chance of an unlikely comeback when he threw away three break points, and Cilic went on to serve out for a career-defining victory in less than two hours.