World number three, Maria Sakkari was knocked out of the US Open in the second round by China’s Wang Xiyu.
Sakkari, who reached the semi-finals in New York last year, won the first set but could not capitalize on her lead, losing 3-6 7-5 7-5.
It is the third time she has lost to a player ranked outside the world top 50 at a Grand Slam this year.