Naomi Osaka begins her U.S. Open title defense in the opening night match in Arthur Ashe Stadium, facing Marie Bouzkova of the Czech Republic. For Osaka, the No. 3 seed who won her second title at Flushing Meadows last year, it's her first Grand Slam match since she pulled out of the French Open after one round for mental health reasons. Another past champion, Sloane Stephens, plays the leadoff match on Ashe against fellow American Madison Keys in a rematch of the 2017 final. They will be followed by Andy Murray, the 2012 U.S. Open champion, against No. 3 seed Stefanos Tsitsipas. Another top contender, No. 2 seed and 2019 runner-up Daniil Medvedev, faces French veteran Richard Gasquet in a night match on Ashe. Coco Gauff, the 17-year-old American seeded 21st, faces Poland's Magda Linette in the last match of the day session on Armstrong Stadium before No. 2 seed Aryna Sabalenka plays Nina Stojankovic there at night. She's followed by Nick Kyrgios against 18th-seeded Roberto Bautista Agut. Two-time Grand Slam champion Simona Halep, who had consecutive first-round losses in New York in 2017-18, has another potential tough test to start. The No. 12 seed faces Italian Camila Giorgi, who won a hard-court title in Montreal, in the opening match on the Grandstand. Then No. 5 seed Andrey Rublev will have to deal with big-serving Ivo Karlovic, who came through qualifying to earn his spot in the main draw.
MONDAY FORECAST
Partly cloudy with afternoon thunderstorms. High of 84 degrees Fahrenheit (29 Celsius).
WHO'S MISSING
Last year's men's champion, Dominic Thiem, is sidelined with an injured right wrist and will not be back to defend his title, and for the second year in a row, Roger Federer and Rafael Nadal are sitting out the U.S. Open. Federer needs another operation on his right knee; Nadal has an injured left foot. Both are done for the year. They share the men's record of 20 Grand Slam singles trophies with Djokovic, who again is seeded No. 1 in New York. Also absent: Serena Williams, owner of 23 major singles championships, and Venus Williams, owner of seven.