As Kei Nishikori contemplated becoming the first Japanese man to reach the U.S. Open's fourth round in the 40-year Open era, he kept repeating two phrases: "I was tired" and "I'm very happy." Overcoming cramps that left his ankles, legs and back aching, the 126th-ranked Nishikori upset No. 4-seeded David Ferrer of Spain 6-4, 6-4, 3-6, 2-6, 7-5 Saturday night. More...