Japan's former world No.1 and two-time Australian Open champion beat Germany's Tamara Korpatsch 6-3 7-6 (11-9) in the first round of the Brisbane International on Monday.
It was the four-time major winner's first WTA victory in 15 months in her first match since the arrival of her daughter in July.
Naomi Osaka mixed winners with unforced errors in a successful return to WTA Tour action.
The 26-year-old thumped 36 winners, mostly on the forehand side, and added 29 unforced errors in a match that stretched almost two hours.
"Part of me felt like Shai was watching me," Osaka said of her daughter, who has remained in the United States
"I wanted to do my best for her."
There were plenty of smiles in a brilliant start, breaking Korpatsch to love in the opening game, before some frustration when she was broken while serving for the match at 5-3 in the second set.
World No.83 Korpatsch then saved two match points and earned two set points of her own in a tense tiebreak that decided a 70-minute second set.
Osaka's big forehand eventually dug her out of that hole, and she enjoyed signing autographs and taking selfies with fans after the match.
"I would prefer what I played," she said when asked if she would rather have notched a straightforward victory.
"I think maybe some of my decisions weren't the best, but it's better to have harder matches because it will train me for what's to come.
"I'm very proud of myself ... all I can think of is, like, the consistent nerves that I had.
"So just getting through that really tough match and hopefully building on it.
"I think my next match will be a really good test on that."
Naomi Osaka was appreciative of the crowd support she received in Brisbane.
That will be against former world No.1 Karolina Pliskova, a three-time winner in Brisbane.
Australia's Arina Rodionova has already progressed to the second round.
Fit-again Daria Saville joined her with a crushing 6-0 6-4 win over Ukraine's Dayana Yastremska on Monday night under a closed Pat Rafter Arena.
Saville will take on world No.28 Anastasia Potapova in the round of 32.
Osaka's and Saville's matches were the only women's matches to be completed on Monday as rain wiped out all play on outside courts, including the scheduled all-Australian clash between Kimberly Birrell and Olivia Gadecki.
Reigning Australian Open champion Aryna Sabalenka, Elena Rybakina, Jelena Ostapenko, Victoria Azarenka, Sofia Kenin and Sloane Stephens are also in the 64-player women's draw, one of the key tune-up events for the Australian Open starting in Melbourne in less than two weeks.
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