After 89 unforced errors, including 14 double-faults, the sixth-seeded American was gone from Flushing Meadows with a loss to 82nd-ranked Renata Zarazua.

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

Novak Djokovic’s first match at the US Open was a bit of a litmus test for the Serbian legend because he didn’t play a hardcourt warm-up tournament coming into the year’s final Grand Slam. The 24-time Grand Slam champion said he didn’t play the Cincinnati Open because he prefers to focus on the Grand Slams at this stage of his career.

Novak Djokovic fears his lack of physical conditioning may come back to haunt him as he chases a record 25th Grand Slam singles title at the US Open.