Aug. 30 (UPI) -- Defending champion and No. 3 seed Naomi Osaka made a triumphant Grand Slam return Monday at the 2021 U.S. Open tennis tournament, pulling away for a straight-sets win over Marie Bouzkova.
Osaka, who skipped Wimbledon after she withdrew from the French Open following the opening round for mental health reasons, defeated Bouzkova 6-4, 6-1 in the first round of this year's tournament in Flushing, N.Y.
Fans attended for the first time since the onset of the COVID-19 pandemic, but they were required to be inoculated against the virus.
The match was tied at 4-all in the opening set before Osaka took control. The Japanese star won the next seven games to build a 5-0 advantage in the second set before losing one game to Bouzkova.
Osaka, a four-time Grand Slam champion, claimed her second U.S. Open title last year after defeating Victoria Azarenka in three sets.
Earlier Monday, Cori "Coco" Gauff rallied for a 5-7, 6-3, 6-4 win over Magda Linette. The 21st-seeded Gauff advances to play 2017 U.S. Open winner Sloane Stephens in the second round.
Simona Halep and Garbine Muguruza also pulled out wins in the opening round in New York. The 12th-seeded Halep held off Camila Giorgi 6-4, 7-6 (3), while No. 9 seed Muguruza reached the next round with a 7-6 (4), 7-6 (5) win over Donna Vekic.
On the men's side of the U.S. Open, third-seeded Stefanos Tsitsipas outlasted Andy Murray 2-6, 7-6 (7), 3-6, 6-3, 6-4 in a grueling five-set marathon that spanned about five hours in high heat and humidity.
Murray, a former No. 1 who won Wimbledon twice and the 2012 U.S. Open, went up two sets to one and appeared ready to become the lowest-ranked man to upset an opponent in the top three at Forest Hills since the computerized ATP rankings started in 1973.
Tsitsipas, however, received treatment from a trainer on his left foot after the third set and battled back to force a decisive fifth. Following a bathroom break after the fourth that bothered Murray, the 23-year-old French Open finalist Tsitsipas went up 2-0 in the final frame and never looked back.
With first-round exits for Murray and 2014 champion Marin Cilic, who was forced to retire due to an injury in the fifth set against Philipp Kohlschreiber, the only male player left in the field with at least one Grand Slam title was top-seeded Novak Djokovic.
Djokovic will debut Tuesday night as he attempts to become the first man since Rod Laver in 1969 to complete a calendar-year Grand Slam.