After winning six matches at Indian Wells to reach the quarter-finals, the rising 21-year-old has now again come through qualifying in the other big US springtime event while reeling off four more victories, headed by Saturday's 7-5 6-4 second-round sensation.
Osaka, the No.15 in the world, couldn't cope with Gibson's searing form as she became the Perth youngster's fourth top-20 victim in the space of three weeks after wins over Ekaterina Alexandrova, Clara Tauson and world No.7 Jasmine Paolini at Indian Wells.
"I was able to draw on some experuiences from Indian Wells to stay calm," said Gibson.
"It's been really cool to see what I am capable of, and it's really exciting for me."
While under pressure from Osaka's big serving for much of the first set, Gibson pounced to break at 5-5 when the 16th seed missed three first serves.
She earned another break at the start of the second set and that proved enough as she remained solid behind her own delivery, not being broken once throughout the whole match while saving the four break points Osaka earned in the hour-and-a-half contest.
Going into the US hardcourt swing, Gibson was ranked 112, but she soared into the top-100 for the first time to No.68 on the back of her run to the last-eight in California. Now, she's threatening to break into the top-60.
In her next round, she'll face another rising star, teenage American world No.17 Iva Jovic, who defeated former world No.2 Paula Badosa 6-2 6-1 on Saturday.
Jovic beat Gibson in a Wimbledon warm up event last year but Gibson noted they have both "come a long way" since June.
"Where we both are right now, I think it's going to be a good battle," she said.
