The U.S. Open said goodbye to its reigning champion Tuesday. Sloane Stephens, last year's U.S. Open women's champion, fell to No. 19 Anastasija Sevastova in the quarterfinals, 6-2, 6-3. Stephens was expected to go far in this year's tournament, and she came into Tuesday's match having beaten Sevastova in two out of three tries.