Wong, who became the first player from Hong Kong to win a Grand Slam singles match since the Open era began in 1968 with his victory in the previous round, produced a composed performance to beat Walton 7-6 (7/5), 6-2, 4-6, 6-4 in three hours.
Wong will face Russian 15th seed Andrey Rublev in the third round on Saturday.
The Hong Kong, China player, who trains at Rafael Nadal’s academy in Mallorca, will head into that contest brimming with confidence after dispatching Walton in style.
Wong, ranked 173rd in the world, reeled off 21 aces and 54 winners in an impressive performance on the Billie Jean King Tennis Center’s outer Court 10.
He quickly recovered from dropping his serve in the first game and broke back for 5-5 as Walton served for the opening set, before going on to win the tiebreak.
He raced through the second set and though he dropped the third, two more breaks of serve in the fourth set up victory. (AFP)