By Amy Tennery

NEW YORK (Reuters) -Mexico’s Renata Zarazua pulled off a stunning upset by beating sixth seed Madison Keys while twice major winner Barbora Krejcikova knocked out promising Canadian teenager Victoria Mboko, as the U.S. Open first round continued on Monday.

Keys finally claimed her maiden major at the Australian Open this year but produced an astonishing 89 unforced errors in the opening match of the day on Arthur Ashe Stadium as she fell to a 6-7(10) 7-6(3) 7-5 defeat.

Zarazua, the only Mexican player in the U.S. Open main draw, saved seven break points across the match on Arthur Ashe Stadium for her first win over a top-10 player in a gruelling, three-hour and 10-minute affair.

“Coming into the match I was like almost crying because I was really nervous but I think the

See Full Page