Rising American star Cori Gauff, 17, says she has a great relationship with Serena and Venus Williams and admitted she gets excited every time Venus comments her Instagram posts. Gauff, who grew up idolizing the Williams sisters, is now one of the brightest stars on the Tour. Gauff is already a top-20 player and she has been tipped by many to win multiple Grand Slams and become the No. 1 one day. Gauff recently gave an interview to People Magazine, in which she spoke about her relationship with the Williams sisters. “We all talk,” Gauff said about the Williams sisters. “Definitely on Instagram, [Venus is] always commenting on my stuff, and it’s pretty cool. She always mentions me on her lives or interviews, a …