Reigning Australian Open champion Madison Keys suffered a shocking upset in the first-round of the 2025 US Open. The American, seeded No. 6 in the women's singles draw of the hardcourt Major, faced Renata Zarazua from Mexico, who is currently ranked outside the WTA top 80. Keys' erratic performance, combined with Zarazua's mature display, led to the Mexican winning the match. Subsequently, several fans slammed the American.On Monday, August 25, the World No. 82 stunned the sixth-ranked Keys 6-7(10), 7-6(3), 7-5 on Arthur Ashe Stadium. The American was a long way away from her best level, producing 14 double faults and 89 unforced errors overall. Even though Keys hit 46 winners, 41 more than Zarazua, the American's errors ultimately resulted in an early exit.Many fans spanning X (formerly Twitter) and Reddit blatantly criticized Madison Keys' performance on the day."Absolute abomination from Madi, she needs to regroup," one fan wrote."Madison Keys had 88 (sic) unforced errors. It was one of the most embarrassing performances I've ever watched," commented another."It felt like Zarazua was giving Keys so many opportunities to take control of the match and lock in but Keys said “no thanks, you can have it” every single time. Just seriously bad day for Keys, which seem to come far too often," another fan chimed in."At least Keys got that Grand Slam in Australia. She played terribly today," opined one."88 (sic) unforced errors, never seen that before in a 3-setter," another added."Keys went from an underdog to a top dog and lost her form. It's so upsetting," weighed in yet another fan."My nerves got the better of me... became a little bit paralyzing" - Madison Keys after suffering defeat at hands of unseeded Mexican in US Open 1RMadison Keys during a press conference at the 2025 US Open (Source: Getty)In the aftermath of the shocking women's singles first-round result, Madison Keys told reporters how the thought of winning the match against Renata Zarazua overwhelmed her internally. Keys claimed that the tension she felt during the match 'paralyzed' her to an extent."I feel like today, for the first time in a while, my nerves really got the better of me, and it kind of became a little bit paralysing. I want to win, but just feeling like winning matters just way too much, and I just couldn’t quite separate myself from that. Then once you start playing badly, it just kind of all snowballs," the 30-year-old said.The early exit from the 2025 US Open marks the end of Madison Keys' Grand Slam season, with its highlight being her title triumph in Melbourne. Meanwhile, Zarazua is now set to face Diane Parry from France in the second round at Flushing Meadows.