Konta came on court immediately after world number one Angelique Kerber's defeat to Daria Kasatkina, while Dominika Cibulkova and Svetlana Kuznetsova, seeded third and fifth respectively, had also crashed out earlier on Tuesday.
That left Konta as the only seed in the top half of the draw and it was not an opportunity the Briton wasted as she battled to a 6-1 6-3 victory over Russian-born Australian Daria Gavrilova in 81 minutes.
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The 25-year-old did not look back after breaking in the opening game and dropped only four points on serve in a first set she dominated.
Konta quickly established herself in the second set and while the plucky Gavrilova staved off four match points on serve in the eighth game, the British number one saved a break point and then sealed the win at the sixth attempt.
"I knew going into the match it was going to be an incredibly tough one, she's one of the best fighters on tour," Konta said of Gavrilova in quotes televised by BT Sport.
The sixth seed continues her preparations for next week's Australian Open with a last-eight clash against Kerber's conqueror Kasatkina, the Russian ranked 16 places below Konta at 26 in the world.
"It's such a strong tournament, such depth, I know going into every single match that it's going to be a tough one and I'm just going to have to, first and foremost, take care of things my end," Konta added.
Konta through to last four in Sydney
Kerber suffers shock defeat in Sydney