Coco Gauff says she often forgets she is still a teenager after becoming the youngest woman to reach the Australian Open singles quarter-finals since 2008.

The 19-year-old American booked her spot in the last eight by sweeping past Poland’s Magdalena Frech 6-1 6-2.

“I’ve lived so many lives in the last four years that I just feel older than 19,” US Open champion Gauff said.

Defending champion Aryna Sabalenka continued her own serene progress by beating Amanda Anisimova 6-3 6-2.

Gauff and 25-year-old Sabalenka remain on course to meet in the Melbourne last four, which would give the Belarusian an opportunity to avenge her defeat in the US Open final.

After bursting on to the scene as a 15-year-old at Wimbledon in 2019, Gauff fulfilled her long-heralded potential by landing a first Grand Slam title in New York.

Now, in her final major tournament as a teenager, she is the second favourite at the Australian Open behind second seed Sabalenka.

“Sometimes I forget my age. I know I’m not going to be a teenager any more,” said Gauff, who is the youngest player to reach the Melbourne quarter-finals since Poland’s Agnieszka Radwanska.

“When I’m looking at the other girls on tour who are 16, 17, and now coming up, they just feel so young and I feel so old.

“I know I’m not that old, but I definitely do forget my age a lot.”

Gauff, who has not faced another seed, will play Ukraine’s Marta Kostyuk next, while Sabalenka faces either 16-year-old Russian Mirra Andreeva or Czech ninth seed Barbora Krejcikova.

Neither Gauff or Sabalenka have dropped a set at the first Grand Slam tournament of the 2024 season.