It was a potential nightmare for fans, tournament organizers and even the players.

Hours after the start of a rain delay Friday afternoon, the wet weather showed no sign of letting up and it was beginning to look like the rest of the day’s schedule at the Pan Pacific Open, including hometown favorite Naomi Osaka’s quarterfinal, would be postponed.

Then, a bit of excitement in the middle of a gloomy evening at Utsubo Tennis Center in Osaka: The world No. 4 emerged from the locker room and greeted the hundreds of rain-soaked spectators who were braving the miserable conditions in hopes of seeing their favorite player in action.

Osaka’s surprise appearance didn’t part the cloudy skies, that’s above even her reach. But in saying hello and uttering a few phrases in the Kansai dialect, she did brighten the mood for a crowd who would have to wait to see their hero on another day. As they spilled out of the 5,000-seat center court, fans were laughing and joking with one another despite the cancellation of the rest of the day’s play.

Such is the popularity of the quirky, soft-spoken Osaka, whose rise to worldwide fame has brought about an increased enthusiasm for tennis in the country and gained her the affinity of the Japanese public, particularly in the city of her birth.

It’s also been a boon for organizers of the 36-year-old tournament, which Osaka went on to win for the first time.

“It’s huge publicity to have her participate,” tournament director Yutaka Nakagawa said in an interview. “There’s a lot of focus and added focus on this tournament from media and fans. More ticket sales and more goods are sold year after year and that’s attributable to her performance.”

Yaeko Takemasa, the chairman of the Japan Ladies Tennis Federation, noted the effect of Osaka’s success on junior players, particularly young girls.

“The influence from Naomi has been very big,” she said, adding that many children have taken up the sport as a result.

Osaka, for her part, pointed to men’s star Kei Nishikori, eight years her senior, when asked about the popularity of the sport in Japan.

“He was kind of carrying it for a while and then I came. I’m not really sure if I can say that I did anything,” she said following one of her two matches Saturday.

“I feel like if there was anyone that’s motivated after watching me play, they’re like a completely new generation.”

But despite the 21-year-old’s modesty, there was little doubt this was her week.

Around the grounds, spectators cooled themselves down with fans adorned with Osaka’s face, waved Japanese flags and carried signs with messages of support for her. One of her top sponsors, Nissin Corp., set up a booth that allowed fans to walk through a makeshift shrine to the two-time Grand Slam champion, complete with a display of a large cut-out of Osaka popping out of a cup of noodles.

Outside the main stadium, a man wearing a wig and dressed in a tennis skirt and tank top took photos with grinning fans. “Futosaka Naomi” (“Fat Naomi Osaka”) says he became a superfan after her U.S. Open win last year and watches all her matches on TV.

“She has a good heart. She’s always worried about how others are feeling,” Futosaka, whose real name is Jiro Tanaka, said when asked what he likes about her. He mentioned her sudden appearance during the rain delay to cheer fans up, as well as an incident in the quarterfinals when her opponent rolled her ankle and Osaka raced to the other end of the court with a towel for her to lie on.

“I’ve never seen anyone do that. She’s so kind,” he said.

Osaka, who moved to the U.S. with her family at age 3, says she has little memory of her time in Kansai — she told reporters she only remembers walking to the park with her mom and sister to get nikuman (meat dumplings). But that doesn’t seem to bother the city’s fans, nor Mayor Ichiro Matsui and Hirofumi Yoshimura, governor of the prefecture, who each presented her with an honorary certificate for top athletes with ties to the area.

Osaka’s roots were widely celebrated during the tournament and, according to the tournament director, that was a “great factor” in the decision to bring it to Kansai before it moves back to its regular home at Tokyo’s Ariake Coliseum next year following Olympic renovations.

“Media talked about it over and over so it was a great way to advertise this tournament,” Nakagawa said.

“Naomi is loved wherever she goes, especially in Japan, but I felt it was completely different (here). Osaka people just love her and loved her coming home. It was like a homecoming and it was very special.”

Osaka was at her best in the championship match on Sunday, painting lines with her world-class forehand and not giving an inch on serve. She never faced a break point in dismantling Anastasia Pavlyuchenkova 6-2, 6-3. But in a rare bit of adversity, Osaka squandered her first two championship points leading her to feign smashing her racket in frustration.

Sensing that she needed a boost, a small child yelled “Naomi ganbare!” (“Let’s go Naomi!”) drawing laughs from the 4,997 in attendance and perhaps easing some of the tension for Osaka.

After dropping that game, she calmly served out the match to win her first title in Japan and, after a monthslong slump, her first title since the Australian Open.

“It’s really special for me to win here,” she said in her victory speech. “This is the city (where) I was born. Honestly, I think that gave me a lot of power to play constantly match after match.”

Later, she reflected more on her win, and about breaking her slump in Osaka.

“I think everything sort of came together. . . . It kinda feels like fate a little bit,” Osaka said.