The 17-year-old American took the round of 32 contest at the Adelaide International in straight sets, winning 6-1 6-2 in a performance described as “flawless” from Roger Rasheed on commentary.
“That was an extremely impressive performance,” Rasheed said on Nine’s coverage.
“From the minute Gauff went out there on the court, she does go to work, there’s no doubt about that. She puts a lot into every part of the tennis match and she was flawless.
“A tough night at the office for Siniakova. When she goes back and sits down and looks at it, she’ll think, ‘Wow, I played a hot Coco Gauff tonight’.”
Gauff was defeated by Ash Barty last week in a tightly-contested match and says she learnt from the loss to the world No.1.
“I’m super happy with how I played today,” she said.
“She’s not an easy player to play, she hits a lot of balls back and is always fighting, but tonight I just think I came out and learnt from my loss last week and made some improvements.”
Gauff will face Ukrainian teenager Marta Kostyuk in the second round.