Australian John Millman has scored one of the biggest wins of his career to charge into the US Open third round in New York.

Millman upset 14th-seeded Italian Fabio Fognini 6-1 4-6 6-4 6-1 to progress to the last 32 for the second straight year at Flushing Meadows.

The Queenslander’s victory set up a clash with unseeded Kazakh Mikhail Kukushkin, himself a surprise straight-sets winner over Korean young gun Hyeon Chung.