Emma Raducanu, of Great Britain, left, shakes hands with Ena Shibahara, of Japan, after winning their first-round match of the US Open tennis championships in New York.

Emma Raducanu, of Great Britain, reacts after beating Ena Shibahara, of Japan, during the first round of the US Open tennis championships, in New York.

Ena Shibahara, of Japan, returns a shot to Emma Raducanu, of Great Britain, during the first round of the US Open tennis championships in New York.

Emma Raducanu, of Great Britain, serves to Ena Shibahara, of Japan, during the first round of the US Open tennis championships, in New York.

Emma Raducanu, of Great Britain, returns a shot to Ena Shibahara, of Japan, during the first round of the US Open tennis championships in New York.

Ena Shibahara, of Japan, returns a shot to Emma Raducanu, of Great Britain, during the first round of the US Open tennis championships, in New York.

Emma Raducanu, of Great Britain, returns a shot to Ena Shibahara, of Japan, during the first round of the US Open tennis championships, in New York.