Iga Swiatek, of Poland, returns a shot to Jasmine Paolini, of Italy, during the first round of the US Open tennis championships, in New York, Aug 30, 2022. (JOHN MINCHILLO / AP)

NEW YORK - Top-seed Iga Swiatek of Poland defeated Italy's Jasmine Paolini, while reigning champion Emma Raducanu ended her title defense after losing to Alize Cornet of France in the first round of the US Open on Tuesday.

Swiatek swept past Paolini 6-3, 6-0 in just 67 minutes. After this win, the French Open champion has become the youngest player to win 45 Grand Slam main draw matches since Caroline Wozniacki did so at the 2011 Australian Open

Swiatek swept past Paolini 6-3, 6-0 in just 67 minutes. After this win, the French Open champion has become the youngest player to win 45 Grand Slam main draw matches since Caroline Wozniacki did so at the 2011 Australian Open.

The 21-year-old Pole will now take on Sloane Stephens of the United States, who rallied past Belgium's Greet Minnen after being one set down.

Emma Raducanu's title defense at the US Open ended after losing 6-3, 6-3 to Alize Cornet, who broke the women's singles record for Grand Slam main draw appearances with 63.

"Really sad to leave here. It's probably my favorite tournament," said the 19-year-old Briton, who became the third female defending champion to lose in the first round of the tournament.

"I'm going to drop down the rankings and climb my way back up. The target is off my back, I have another chance to claw my way back up there," she added.

Cornet will next meet Katerina Siniakova of the Czech Republic, who eliminated American Taylor Townsend.

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Zheng Qinwen hits a return to Jelena Ostapenko of Latvia during the first round of the US Open tennis championships in New York, Aug 30, 2022. (LIU JIE / XINHUA)

Meanwhile, fourth-seeded Paula Badosa reached the second round after beating Ukraine's Lesia Tsurenko, while 42-year-old Venus Williams was eliminated by Belgium's Alison Van Uytvanck.

On the men's side, 22 times Grand Slam champion Rafael Nadal came back to beat Australian wild card Rinky Hijikata 4-6, 6-2, 6-3, 6-3.

"I'm very happy to be back. It's a long time since I played here," said the Spanish legend, who last appeared at US Open in 2019 and won that title, will next meet Italy's Fabio Fognini.

Nadal's compatriot Carlos Alcaraz progressed after the retirement of Sebastian Baez due to injury after taking the first two sets 7-5, 7-5, and leading the third 2-0.

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The 19-year-old rising star's next opponent will be Federico Coria of Argentina, who knocked out Tallon Griekspoor of the Netherlands in straight sets.

China's Zheng Qinwen defeated former French Open champion Jelena Ostapenko 6-3, 3-6, 6-4, while Yuan Yue swept past Australian wildcard Jaimee Fourlis 6-3, 6-2 as both Chinese youngsters took their first main draw victories at the US Open.