Melbourne (AFP) - Coco Gauff said she was enjoying “learning adulthood” after showing poise and determination to storm into a first Australian Open quarter-final on Sunday.

The 19-year-old fourth seed was again in the zone to race past unseeded Magdalena Frech 6-1, 6-2 in just 63 minutes on Rod Laver Arena as she zeroes in on a second Grand Slam title.

The US Open champion, who had never progressed beyond the fourth round at Melbourne Park in four previous attempts, has been in red-hot form and is yet to drop a set.

She is now on a nine-match win streak following her title run at Auckland and will meet Ukrainian Marta Kostyuk for a place in the semi-finals.

Gauff made her Grand Slam debut at Wimbledon as a 15-year-old, and it has been a learning process ever since, guided by her parents.

But she is now starting to take charge of her own destiny, on and off the court.

“As each season goes, I’ve definitely been more vocal about what I want on and off the court,” she said.

“At first, like 15, 16, my parents were doing a lot of it for me just so I could focus on tennis. Now I’m moving into more of the role. I’m getting older, having to make more decisions, all of that, on and off court.

“I think for me, I know myself pretty well. I know what I need to do to succeed, not every single thing. That’s why we have coaches and people that advise me.

“It’s definitely been a process with each year. Adulthood is something I’m really enjoying learning. I’m not completely there, but every year I think I’m getting better and better at it.”

With seven of the women’s top 10 seeds knocked out in the first week, Gauff has a clear-cut chance to add to her US Open title, with a potential showdown against defending champion Aryna Sabalenka looming in the semi-finals.

She wasted no time letting Frech know who was in charge, breaking her opponent in her opening service game with a forehand winner and breaking twice more as she romped through the set in just 26 minutes.

The American won 17 of 22 points from the baseline, and all four at the net.

She continued in the same vein in set two, breaking for 3-1 and never relenting to charge home.

Despite the ease of her progress into the last eight, Gauff said she did not feel “uncooked”.

“US Open I did play higher-ranked people earlier. That’s also another reason why I had so many long matches,” she said.

“It doesn’t feel different. I know when it comes to crunch time, if I have a long match the round before or not, I’ll still compete the same and still feel just as sharp.”