Coco Gauff, of the United States, cries after defeating Donna Vekic, of Croatia, during the second round of the U.S. Open tennis championships in New York.

Coco Gauff, of the United States, acknowledges the crowd after defeating Donna Vekic, of Croatia, during the second round of the U.S. Open tennis championships in New York.

Gymnast Simone Biles, center, reacts after Coco Gauff, of the United States, mentioned her following Gauff's match against Donna Vekic, of Croatia, during the second round of the U.S. Open tennis championships in New York.

Donna Vekic, of Croatia, returns a shot to Coco Gauff, of the United States, during the second round of the U.S. Open tennis championships in New York.

Coco Gauff, of the United States, serves to Donna Vekic, of Croatia, during the second round of the U.S. Open tennis championships in New York.

Coco Gauff, of the United States, appears to cry after winning the first set over Donna Vekic, of Croatia, during the second round of the U.S. Open tennis championships in New York.

Donna Vekic, of Croatia, flips her racquet after losing a point to Coco Gauff, of the United States, during the second round of the U.S. Open tennis championships in New York.

Donna Vekic, of Croatia, serves to Coco Gauff, of the United States, during the second round of the U.S. Open tennis championships in New York.

Coco Gauff, of the United States, returns a shot to Donna Vekic, of Croatia, during the second round of the U.S. Open tennis championships in New York.

Donna Vekic, of Croatia, serves to Coco Gauff, of the United States, during the second round of the U.S. Open tennis championships in New York.