Japan's Naomi Osaka advanced to the second round of the U.S. Open for the sixth straight year Monday, the reigning champion beating Marie Bouzkova of the Czech Republic 6-4, 6-1.

Third seed Osaka survived three break points in the third game before getting the first break of the match in the 10th game to claim a tight first set at Arthur Ashe Stadium.

The four-time grand slam winner tightened up her groundstroke play in the second set to break twice and brush aside her 87th-ranked opponent.

Naomi Osaka of Japan returns a shot during her women's singles first round match against Marie Bouzkova of the Czech Republic at the U.S. Open in New York on Aug. 30, 2021. (Getty/Kyodo)

Osaka, who went out in the third round in both the Tokyo Olympics and the Western & Southern Open recently, said she enjoyed having the New York crowd back after the tournament was held without spectators last year due to the COVID-19 pandemic.

Spectators attending the tournament this year must be vaccinated against COVID-19.

Osaka won her first grand slam at the 2018 U.S. Open when she beat her idol, Serena Williams, before getting her second win at the tournament last year. She also won the Australian Open in 2019 and 2021.

Taro Daniel was defeated 6-3, 6-3, 6-3 by Facundo Bagnis of Argentina in the men's singles first round, with Yuichi Sugita also going out 6-3, 6-2, 6-2 at the hands of Casper Ruud of Norway.

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