Madison Keys, the champion of the Australian Open, exits the U.S. Open in the opening round. In dazzling sunlight at Arthur Ashe Stadium, Renata Zarazúa, the No. 82 seed in the world from Mexico, ...

QUEENS, NY — Australian Open champion Madison Keys suffered a shock first-round defeat against Mexico's Renata Zarazua amid searing heat at Arthur Ashe Stadium on Monday afternoon. Keys, the world No.