The teenage American – who was not even born when Williams had won her first two Wimbledon singles titles – showed not an ounce of fear on Court One, making light of the 24 years age difference.
“I don’t really know how to feel,” said 313-ranked Gauff, who sunk into her chair and cried in the aftermath of her victory.
“This was definitely the first time I ever cried after a match, winning!”
Gauff, who said she took up tennis due to the exploits of Venus and her younger sister Serena, was watched by her family and paid tribute to them.
“I don’t even know what my parents will be saying,” she said.
“I’m just so happy and blessed that they spent all their time on me and my brothers in making sure that we’re successful.
“I never thought this would happen. I’m literally living my dream right now. Not many people get to say that.”
Williams had looked increasingly lost during the encounter, although she did break back in the second set and saved several match points, but sank to her knees by her racquet bag before walking off without waiting for the youngster.
“She (Williams) just told me congratulations and to keep going and good luck,” said Gauff, who won the French Open junior girls title last year.
“I told her thank-you for everything she did.
“I wouldn’t be here if it wasn’t for her.
“I was telling her that she was so inspiring. I always wanted to tell her that.”