Australian No.1 Alex de Minaur has battled through to the third round of the US Open after outlasting French veteran Richard Gasquet 6-4 6-3 6-7 (8-6) 7-5.

De Minuar looked to be cruising to victory when he raced into a two-set lead and held three match points in the third, only for Gasquet to drag himself off the canvas to win the last five points of the tiebreak.

The sweet-swinging 2013 semi-finalist then raced into a 3-0 lead in the fourth set following an early break of the 21st-seeded de Minaur.

But the fleet-footed Sydneysider showed all his renowned fighting qualities to level the set in sweltering conditions in New York and then broke the former world No.7 to win an entertaining three-hour encounter.

De Minaur, who reached the fourth round at Flushing Meadows last year, will now face giant Russian 11th-seed Russian Karen Khachanov.

Khachanov booked his third round spot with a 6-3 6-4 6-1 win over compatriot Andrey Kuznetsov.