The U.S. Open is unpredictable and No. 7 ranked Simona Halep learned the hard way Monday.

The two-time Grand Slam champion suffered a devastating loss to Ukrainian qualifier Daria Snigur. It was the first tour-level win for Snigur topping Halep 6-2, 0-6, 6-4. She held back tears as she explained what the win meant for her and her country, which is dealing with Russia’s invasion.

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"I’m very happy. I’m very, very, very nervous. But I tried to do my best," she said, via WTATennis.com.

She wore a blue ribbon in the colors of the Ukraine flag – blue and yellow. She was on the same court — Louis Armstrong Stadium — where she participated in the "Tennis Plays for Peace Exhibition" to raise money to aid Ukraine.

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"I think it helped me because I was here in ‘Tennis Plays for Peace’ and I think it helped me a little bit," she said.

Halep had won 19 of her last 22 matches and made a return to the top 10 in the WTA rankings. She was seeded No. 7 coming into the tournament. She is 21-11 in New York ad has lost in the first round of three of her last five appearances. She last won a Grand Slam in 2019 at Wimbledon.

Snigur, 20, was ranked as high as No. 2 on the junior circuit. She lost to Simona Waltert in the quarterfinal of the TF Bronx W60 event before getting a crack at her first Grand Slam event.

The Associated Press contributed to this report.