The 32 seeds received first-round byes, including US Open champion and top seed Aryna Sabalenka.
Top-ranked Iga Swiatek was not playing this week for personal reasons.
Japan Open
Top-seeded Taylor Fritz was upset by No. 24-ranked Arthur Fils of France 6-4, 3-6, 6-3 in Tokyo.
Fils peeled off 32 winners in a power-hitting display against Fritz, who made his first Grand Slam singles final at the US Open this month. Fils has former top-10 player Matteo Berrettini in the second round.
Defending champion Ben Shelton shook off a rusty first set to beat countryman Reilly Opelka 3-6, 6-1, 6-4. Shelton, along with Fritz, came from the Laver Cup in Berlin where they represented Team World in a loss to Alcaraz’s Team Europe.
“I felt like I was struggling a little bit and getting rhythm,” the eighth-seeded Shelton said. “Reilly was serving and returning extremely well.”
No. 12-ranked Stefanos Tsitsipas, who was at the Laver Cup for Team Europe, lost to Alex Michelsen of the USA, 4-6, 6-1, 6-2.
Brandon Nakashima won another all-American tie against US Open semifinalist Frances Tiafoe 7-5, 6-3. Nakashima, ranked 36th, fired 12 aces.
Fifth-seeded Tommy Paul rolled to a 6-3, 6-2 win over Italy’s Matteo Arnaldi. Other winners included US Open semifinalist Jack Draper, Tomas Machac, and Yoshihito Nishioka, who outlasted Felix Auger-Aliassime 7-6 (5), 3-6, 7-6 (5) in a three-hour match.
