MELBOURNE, Australia (AFP) — Rising teenage star Coco Gauff warned at the Australian Open that her "best is yet to come" as she goes in search of a maiden Grand Slam crown.

The 18-year-old American has the honor of playing in Monday's opening match on the showpiece Rod Laver Arena against the Czech Republic's world No. 48 Katerina Siniakova.

Seventh-ranked Gauff heads into the first Grand Slam of the year on a high after winning her third WTA title at the Auckland Classic earlier this month.

She is riding at her highest career ranking after breaking into the top 10 last year and reaching a Grand Slam final for the first time, losing to Iga Swiatek at Roland Garros.

"As much as I would like to think this might be the best I'll be, I don't believe it because I feel like most of the tennis players, at least on tour now, are peaking in their career around 22 to 26," Gauff said.

Gauff first won hearts as a 15-year-old in 2019 at Wimbledon when she arrived as a qualifier and reached the last 16, beating five-time champion Venus Williams along the way.

"From 15 when I started to now I realize physically I'm at a much different level than I was at 15. I think I'm just continuing to get stronger," Gauff said.

"There's a joke that my mum has. She is like, 'You don't have that grown woman strength yet. You'll know when you get it.'"

"I can't put a percent on it, but I know the best is yet to come for me."

Gauff would become the youngest Australian Open champion since a 16-year-old Martina Hingis in 1997 if she goes on to lift the winner's Daphne Akhurst Cup, but she said she almost feels like a veteran.

"I think I've been on tour for four years now. I don't know how I feel. I definitely feel more experienced and like I belong," said Gauff, who won her first WTA Tour title in 2019.

"I don't feel like the new kid, but I don't think I feel like a vet. I feel like I'm in the middle of the pack."