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. 6, made a staggering 89 unforced errors in a marathon match against the 95th-ranked Zarazua, who recorded by far the biggest win of her career against the hometown favorite on Monday.

Zarazua recovered from being a set and a break down to win 6-7 (10), 7-6 (3), 7-5 against a fancied Keys that had not suffered a first-round loss in any of her previous 15 grand slam appearances.

Keys, who won her maiden slam title Down Under in January, was sluggish throughout but appeared set to avoid a banana skin after taking a mammoth first-set tiebreaker and racing into a 3-0 lead early in the second.

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