Defending champion Coco Gauff wasted no time launching her U.S. Open title defense, taking down first-round opponent Varvara Gracheva of France 6-2, 6-0 in 66 minutes on Monday in New York.

Gauff claimed her first Grand Slam title last year at Arthur Ashe Stadium and entered this year's tournament looking to recapture that form after a disappointing summer of results.

"If you defend something, that means you won something, and if you did it, that means you can do it again," Gauff said in her on-court interview. "So whether I do it again this year or not, I'm gonna do it again. Whether it's 2024 or not, I will do it again."

The third seed in this week's main draw, Gauff cruised against Gracheva, who's ranked 66th in the world. Gauff finished with a 10-0 edge in aces, went 9-for-9 saving break points and finished with a 16-5 advantage in total winners.

Gauff broke Gracheva's serve twice in the first set to take control. She won the final nine games in a row spanning the first and second sets.

The 20-year-old Gauff earned her 15th match win at the U.S. Open, the youngest woman to hit that milestone since Caroline Wozniacki in 2010.

Gauff advanced to face Tatjana Maria of Germany in the second round. Maria was a 6-2, 6-3 winner over Solana Sierra of Argentina.

American women had a tremendous start to the tournament. No. 13 seed Emma Navarro, who upset Gauff at Wimbledon to reach the quarterfinals there, took down Russia's Anna Blinkova 6-1, 6-1 in 59 minutes. No. 14 seed Madison Keys beat Katerina Siniakova of the Czech Republic 6-4, 6-1 in 64 minutes.

Other Americans winning Monday included Peyton Stearns, Taylor Townsend and 16-year-old Iva Jovic, who beat Poland's Magda Linette in straight sets in her Grand Slam debut. However, 2017 U.S. Open champion Sloane Stephens lost 0-6, 7-5, 7-5 to France's Clara Burel.

On a packed first day of main-draw action in New York, it did not take long for the first top-10 seed to fall. Greece's Maria Sakkari, the ninth seed, dropped her first set 6-2 to China's Yafan Wang before retiring due to the shoulder injury that led to her withdrawal from recent tournaments in Toronto and the Cincinnati area.

Wang's next opponent will be Diane Parry of France, who took down China's Xiyu Wang 7-6 (2), 7-6 (5).

No. 7 seed Qinwen Zheng of China hit 12 aces and saved 8 of 12 break points on her way to a 4-6, 6-4, 6-2 win over American upstart Amanda Anisimova. Zheng moved on to face Russian Erika Andreeva, who rallied in her second-set tiebreaker to finish off China's Yue Yuan 6-3, 7-6 (7).

Germany's Jule Neimeier outlasted No. 32 Dayana Yastremska of Ukraine 6-4, 6-7 (3), 6-4. Other winners included No. 8 Barbora Krejcikova of the Czech Republic, No. 12 Daria Kasatkina of Russia, No. 13 Emma Navarro of the United States, No. 19 Marta Kostyuk of Ukraine, No. 20 Victoria Azarenka of Belarus, No. 24 Donna Vekic of Croatia, No. 26 Paula Badosa of Spain, No. 27 Elina Svitolina of Ukraine and No. 29 Ekaterina Alexandrova of Russia.

Greet Minnen and Elise Mertens of Belgium, Anhelina Kalinina of Ukraine, Moyuka Uchijima of Japan, Harriet Dart of Great Britain, Elena-Gabriela Ruse of Romania, Lucia Bronzetti of Italy and Australians Maya Joint and Ajla Tomljanovic also advanced.

In the last match of the night, second-seeded Aryna Sabalenka of Belarus routed Australian qualifier Priscilla Hon 6-3, 6-3.

--Field Level Media