Madison Keys made so many mistakes that Renata Zarazua needed to produce just eight winners to earn the biggest victory of her career.

Australian Open champion Madison Keys has been undone by 89 unforced errors during a 6-7 (10), 7-6 (3), 7-5 loss to Mexico’s Renata Zarazua in the first round of the U.S. Open

Zarazúa also became the first Mexican woman to ever beat a top-10 opponent at the U.S. Open. Keys, who prevailed in a twisting first-set tiebreak and then took the first three games of the second set at a clip,