The 20-year-old and Poland's Iga Swiatek loom as the biggest threats to Aryna Sabalenka's quest for three straight titles at Melbourne Park.
Gauff made the final four last year, her best result at the tournament, but was knocked out by Sabalenka in two tight sets.
Should things go their way, the pair are on track for another semi-final showdown.
Gauff said she was more confident in her game than when she won the US Open in 2023 and became the first American teenager to lift the trophy since Serena Williams in 1999.
She is coming off an impressive end to 2024, which included a win over Sabalenka en route to claiming the WTA Finals in Saudi Arabia.
Her Australian summer started with an undefeated United Cup, including success over Swiatek.
View this post on Instagram A post shared by Coco Gauff (@cocogauff)
Gauff, who meets fellow American Sofia Kenin in the first round, said the addition of Matt Daly to her coaching team had come with tweaks to her serve.
"I feel more comfortable now than ever," she told reporters.
"Not even from the fact of the (coaching) changes. I just realised the importance of winning or losing a match.
"As athletes ... losing feels like the end of the world ... I think I just realised it's never that important.
"If I can step off the court and say I tried my best, that's all I can ask for."
While Gauff enters the first grand slam of the year with a clear head, Swiatek does so after a doping controversy.
The world No.2 pulled out of the tour in September for "personal reasons" - it was later revealed she had accepted a one-month ban after testing positive for a banned heart drug.
Swiatek denied knowingly breaking regulations, saying the result came from contaminated non-prescription medication.
In her final press conference before the Open, Swiatek said it was the "worst time of her life" and she feared what fellow competitors would think.
Iga Swiatek comes into the AO as the world No 2. but after a recent doping suspension.(Mark Evans/AAP PHOTOS)
"Besides the fact I couldn't play, this was the worst thing for me," said.
"I always worked hard to be a good example, to show my integrity and show good behaviour.
"But in the locker room the girls are great. I already saw (in an) exhibition in Abu Dhabi that they are really supportive.
"Most of them even approached me. They're like 'hey, how can we avoid this? Is there any way that we can be more careful?'"
Gauff has defended Swiatek, saying she didn't think the positive result happened because of anything intentional.
Swiatek's level has perhaps dropped since the ban, but Gauff said she hadn't noticed a change.
"The match we played, I just happened to be a little better that day, maybe won a few points," Gauff said.
"She's still No.2 in the world and playing amazing tennis."
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