Thanasi Kokkinakis was no match for Yu Hsiou Hsu of Taiwan, going down 3-6 4-6 6-3 3-6 in a disappointing result for the World No.78. At World No.237, Hsu is ranked 159 places lower than Kokkinakis.
It will be a bitter exit from the US Open for the Aussie star considering his record at grand slam level. He has now lost in the first round in four of his last eight appearances at majors.
Hsu will play No 16 seed Cameron Norrie next.