One of the upcoming players from the US is Sloane Stephens (#110). She made a big splash in this year's US Open as she reaches the third round! In the first round, she took care of Hungarian Reka-Luca Jani (#222) 62 36 76(3), then defeated Israeli ace Shahar Peer (#24) 61 76(4) in the second round. In the third round, she fell to former world #1 player, Ana Ivanovic (#19) 36 46.
For her efforts here, her ranking has zoomed to #89 this week, her highest ranking ever.