Venus Williams overpowered Mona Barthel of Germany 6-3, 6-1 on Sunday to advance to the second round of the Pan Pacific Open.
Williams needed just 1 hour, 4 minutes at Ariake Colosseum to dispatch Barthel and set up a second-round matchup with top-seeded Victoria Azarenka, who has a first-round bye.
Williams is 2-0 in head-to-head matches against Azarenka. They last met three years ago in the Dubai Duty Free final.
"I've watched many of her matches," Williams said. "Especially the big matches against Serena. Watching them at the U.S. Open was awesome, and hopefully that will help me."
Top-ranked Serena Williams, who won her 17th Grand Slam singles title with a three-set win over Azarenka at the U.S. Open, pulled out of the $2.3 million tournament, saying she needed time to recover from a busy summer playing schedule.
No. 3-ranked Maria Sharapova also pulled out of the Tokyo tournament because of a right-shoulder injury that kept her out of the U.S. Open.
In other matches, ninth-seeded Sloane Stephens of the United States beat Stefanie Voegele of Switzerland 6-3, 6-2 while 12th-seeded Samantha Stosur of Australia came from a set down for a 2-6, 6-4, 6-1 win over Alize Cornet of France.
Kirsten Flipkens of Belgium, seeded fourteenth, defeated Barbora Zahlavova Strycova of the Czech Republic, 7-6 (4), 7-5.
Sorana Cirstea of Romania beat Julia Goerges of Germany, 6-4, 6-4.