Top seeds Jessica Pegula and Tommy Paul powered into the Adelaide International semifinals on Thursday with straight-set wins as they play themselves into form days before the Australian Open.
The American duo allowed their opponents few chances in quarterfinal routs, with Pegula dispatching fatigued compatriot Ashlyn Krueger 6-4, 2-0 through retirement.
Krueger, a lucky loser from qualifying, was feeling the effects of nine matches over the past 12 days in Brisbane and Adelaide.
World No 7 Pegula, last year's US Open finalist, played doubles with Krueger this week and knew her partner was tired.
"It's never fun to win with a retirement," said the 30-year-old.
"I knew she had a tough singles yesterday. But coming out you never know what to expect, she was still playing amazing tennis."
She will face Yulia Putintseva for a place in the final after the Kazakh player took more than three hours to beat world number 13 Diana Shnaider 7-6 (7/3), 6-7 (9/11), 6-4.
Russia's Liudmila Samsonova earned her first top-10 win in more than a year when she ousted world No 8 and second seed Emma Navarro, 6-4, 6-4.
Samsonova will face Madison Keys next after the American upset third seed Daria Kasatkina 6-1, 6-3.
In the men's draw, Paul duplicated his final-four place in Adelaide from 2020 with a 6-3, 6-4 defeat of Australian Rinky Hijikata.
He will now face Canadian fifth seed Felix Auger-Aliassime, who defeated American Marcos Giron 7-6 (7/3), 6-3.
"That's a big match," said Paul, who is seeking a fifth ATP Tour title.
"The more time on court the better for me."
Serbia's Miomir Kecmanovic surged into the last four with a 6-2, 6-3 defeat of French qualifier Benjamin Bonzi.
His reward is a clash with American second seed Sebastian Korda, who had a walkover after Australia's Thanasi Kokkinakis pulled out injured.