Gauff and her fans were reacting excitedly to quite a point
Gauff, the French Open runner-up in June, came back in each set to beat China's Zhang 7-5, 7-5 on Sunday
the youngest American to make it this far at the US Open since Melanie Oudin was 17 in 2009.
Gauff was buoyed by spectators who cheered her every point and chanted
She praised Gauff's play, calling her "a superstar'' and adding
She's so much younger than me. Her energy is so much better. She's faster. She's powerful.''
Everyone has known how talented Gauff is for a while now.