Australian Open champion Madison Keys was undone by 89 unforced errors and was upset in the first round of the U.S. Open by Mexico’s Renata Zarazua on Monday.

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. 6, made a staggering 89 unforced errors in a marathon match against the 95th-ranked Zarazua,