NEMURO, Hokkaido--When Naomi Osaka hoisted the U.S. Open trophy, it also lifted the spirits of her grandfather here, who has been struggling since a powerful earthquake struck Hokkaido on Sept. 6.

Tetsuo Osaka, 73, was watching the women's singles final on TV at home here, the southeastern tip of the northern main island, with his family on the early morning of Sept. 9 as his granddaughter became the first female Grand Slam singles tennis champion born in Japan.

“I was simply stunned,” Tetsuo said. “I didn’t expect her to become the champion.”

Osaka called him from New York after the final.

“She said, ‘I did it,’ and I said, ‘You did a great job.’”

Tetsuo, who is the chief of Nemuro’s fishery cooperative, and his neighbors, too, are still wrestling with an unstable power supply and food shortages, triggered by the magnitude-6.7 earthquake that rocked much of the southern part of Hokkaido early on Sept. 6.

Tetsuo watched Osaka's semifinal match on Sept. 7, in Japan time, at his relative’s house as his home was without power due to the earthquake.

“I am truly happy for my grandchild, but people were killed by the earthquake,” Tetsuo said, acknowledging the victims of the temblor. “There are many people who have no time to care about tennis.”

Tetsuo, who has been watching Osaka play since she was 12 or 13, said he noticed how she has matured as a tennis player. Osaka kept her composure and focus while 23-time Grand Slam champion Serena Williams smashed her racket on the court and went off on fierce, long harangues against the chair umpire during their match.

“Naomi remained unshaken even though there were such setbacks. She could keep her concentration and disposition,” said Tetsuo. “That’s the reason she could win.

Osaka will be returning to Japan to play in the Toray Pan Pacific Open Tennis Tournament in Tokyo, which starts on Sept. 17. Tetsuo is planning a visit to Tokyo to see his granddaughter.

“Naomi won one of the Grand Slam tournaments, but I want her to become a tennis player who is modest and not arrogant. As she becomes a better player, I would like her to become a better person," he said. “As she is still young, she might get a big head. I am hoping to guide her to prevent that as much as I can.”