The world number 301 on Monday defeated Venus 6-4, 6-4 in a match that lasted for an hour and 19 minutes.
"I'm super shocked, but I'm just super blessed that Wimbledon decided to give me the wild card," the WTA website quoted Gauff as saying in her post-match press conference. "I mean, I never expected this to happen.
"Obviously I literally got my dream draw, so I'm just super happy I was able to pull it out today. She played amazing, was just super nice. She's always been nice the couple times I met her," she added.
The 15-year-old, who is the youngest player ever to qualify for Wimbledon in the Open Era, took out a player who is 24 years her senior, setting a record for the match with the biggest age difference between opponents at the grass-court event. She didn't look nervous by the occasion and went to toe to toe with one of the legends of the game.
"On the court, I was not thinking about Venus - I was just playing my game," Gauff said.
The American teen insisted that she wants to be the greatest tennis player.
"I said this before: I want to be the greatest," Gauff said. "My dad told me that I could do this when I was eight. Obviously you never believe it. I'm still, like, not 100 per cent confident, but you have to just say things.
"You never know what happens. If I went into this match saying, 'Let's see how many games I can get against her,' then I most definitely would not have won. My goal was to play my best. My dream was to win. That's what happened."
She will next face Magdalena Rybarikova, who defeated No.10 seed Aryna Sabalenka in her first round contest.
( With inputs from IANS )