The No.7 seed let out an emotional roar after triumphing 6-4 6-4 against the local favourite at John A Harris Grandstand on Friday.
De Minaur dished out six aces in the win over the No.14 seed. He won 67 per cent of points on his first serve and 64 per cent on his second.
The 26-year-old from Sydney faced a break point while serving for the match, but then nailed a backhand volley to level the game, before advancing in 95 minutes.
De Minaur will now meet Frenchman Corentin Moutet for a place in the final, where American Ben Shelton or Spaniard Alejandro Davidovich Fokina awaits.
Earlier, Moutet put paid to the hopes of No.8 seed Daniil Medvedev, winning 1-6 6-4 6-4.
Medvedev loves playing on hard courts and in particular the US Open, and his loss was an upset with the grand slam just a month away.
The Russian has reached six grand slam finals in his career - all on hard courts.
"Usually, this is the most important part of the season for me," Medvedev said after the loss.
"And this year, it's really important for me, because I didn't have the best year. I had a lot of time after Wimbledon, so I'm feeling ready and I feel in good shape."
No.4 seed Shelton eliminated sixth-seeded Frances Tiafoe in an all-American affair, winning 7-6 (7-2) 6-4.
Shelton hurled down nine aces to Tiafoe's eight in the closely fought contest.
And in the late quarter-final, Spanish 12th seed Davidovich Fokina booked his spot in the semis by upsetting top-seeded American Taylor Fritz 7-6 (7-3) 3-6 7-5.
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