Former World No 1 Angelique Kerber eliminated local favourite Naomi Osaka in the first round of the Toray Pan-Pacific Open on Monday.
The German cruised to a 6-3, 6-4 victory in Tokyo to set up a second-round clash with either Madison Brengle or Daria Kasatkina.
"It's really nice being back," said Kerber after the match. "It's always a great tournament and I always look forward to coming back to Tokyo and the Japanese fans. I'm happy to have won my first round and am looking forward to the next round."
Kerber was able to exact some measure of revenge for the straight sets victory Osaka inflicted upon her at the recent US Open.
"It's always tough to play against her," she added. "I was trying to come out here and really focus on every single point and make it better than last time...she's a great player, great, talented player and tough opponent. For sure she will have great success in the future."
In other first-round results, another local hope, wild card Kurumi Nara, battled past Yulia Putintseva of Kazakhstan 2-6, 6-4, 6-2.
China's Wang Qiang, meanwhile, thrashed Kristina Mladenovic of France 6-0, 6-0.
The tournament was also hit with the withdrawal of two-time champion Agnieszka Radwanska, who pulled out with a virus.