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.
Sabalenka will face ninth seed Barbora Krejcikova, who fought back to beat Mirra Andreeva 4-6 6-3 6-2 and end the 16-year-old’s impressive run in Melbourne.
Gauff and 25-year-old Sabalenka remain on course to meet in the 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.
Seeded players have been falling quickly in the women’s singles, with only four of the top 16 left after the first week and just seven remaining in total.
Belarusian Victoria Azarenka, seeded 18th, is the only Grand Slam champion left in the top half of the draw after world number one Iga Swiatek’s shock third-round defeat on Saturday.
Gauff, 19, ensured she did not face the same fate with a clinical and composed performance against Frech, who was competing in the last 16 of a major for the first time.
The American broke serve in the first game on and allowed Frech to win just 10 more points in a 26-minute set.
Two more breaks of serve followed in the second set as Gauff breezed through without facing a break point.
In her first Melbourne quarter-final, she will face Kostyuk after the world number 37 easily beat Russian qualifier Maria Timofeeva 6-2 6-1.
Gauff said she was “not too nervous” to play in front of the great Rod Laver – because she was already well on the way to victory when the 11-time major champion arrived on the court named after him.
“Luckily I was up a lot when I noticed he came in,” joked Gauff, who thanked the 85-year-old Australian for coming to her match.