Coco Gauff will face Danka Kovinic in the Auckland WTA semi-finals after breezing through with a straight sets dismissal of China's Zhu Lin.
The tournament top seed's progression never looked in doubt during a 6-3 6-2 victory.
However, third seed Leylah Fernandez has been dumped out of the event, losing 6-4 6-2 to unheralded Belgian Ysaline Bonaventure.
Fernandez was on fire at the ASB Classic until Friday, winning her first two matches for the loss of just three games.
Her streak was ended by the big hitting Bonaventure, who won through to her first WTA semi-final appearance.
Amid unseasonably wet weather on Friday, the Australian Open lead-up event again went indoors for the quarter-finals, played without fans on training courts.
Gauff, the world No.7 was unchallenged on serve early but took her time to break the world No.84, unable to convert her first seven break points.
The 18-year-old finally took a chance in the eighth game, then racing to take the set with another dominant service game.
With her booming backhand in full swing, Gauff claimed an early break in the second set and looked assured as she closed out the match in 77 minutes.
The American is now two victories away from a third career WTA singles title and her first since May 2021.
Tournament favourite Gauff has been untroubled in her three matches in Auckland, also beating world No.68 Tatjana Maria and Sofia Kenin, the 2020 Australian Open winner, in straight sets.
"Today was definitely the best match I've played so far," Gauff said.
"Each match I'm improving and that's what I love to see."
The indoor courts have created controversy this week after Britain's Emma Raducanu retired due to an ankle injury, criticising the surface.
Gauff - who also beat Kenin indoors - said the pace of the courts would be great preparation for the slick surfaces awaiting her at Melbourne Park.
"Outdoors is a little bit more grittier. Indoors is a bit slicker," she said.
"For me, the faster courts I can play on, especially preparing for the tournament, will help.
"But it is tough indoors (without fans). There's not a lot of energy moving in the air so you have to bring it."
Tournament director Nicolas Lamperin defended the courts, saying they were the same as those outside and that Raducanu's injury could have happened anywhere.
Gauff's opponent in the last four will be seventh seed Kovinic, from Montenegro, who won through 6-3 6-2 against Viktoria Kuzmova.