NEW YORK - Defending champion Naomi Osaka of Japan and Greek third seed Stefanos Tsitsipas were both ousted from the US Open by 18-year-olds in epic stunners on Friday at Arthur Ashe Stadium. Four-time Grand Slam champion Osaka was shocked by Canadian left-hander Leylah Fernandez 5-7, 7-6 (7/2), 6-4 after Spain's Carlos Alcaraz upset French Open runner-up Tsitsipas 6-3, 4-6, 7-6 (7/2), 0-6, 7-6 (7/5). "Hone