De Minaur overcame Andreas Seppi of Italy 7-5, 7-6 (5) in Saturday's singles final.
De Minaur was due to take on Simon in the semi-final on Friday night, but persistent rain means only the women's semi-final will begin if the weather clears.
The youngster ended his Sydney campaign in the best possible way, beating Andreas Seppi 7-5, 7-6 in the final to lift his maiden ATP title and become the first ATP victor born in 1999!More news: Cameron church celebrates safe return of Jayme Closs
In doing so, he became the youngest victor of the Sydney International since Lleyton Hewitt in 2001, and the first home talent to claim the prize since Bernard Tomic in 2013.
The 34-year-old Italian's efforts paid off when he broke De Minaur to go 4-3 up but a poor service game allowed the teenager to break straight back and the set headed into a tiebreak.
A tournament win in Sydney would be de Minaur's first on the world tour, after he reached two senior finals past year and lost both, as well as the Next Gen decider in Italy.More news: South Africa vs Pakistan
TEENAGE tennis sensation Alex de Minaur has accused Australian Open organisers of punishing local players who perform well in home tournaments, after failing to have his opening-round clash at the grand slam pushed back. The feisty 19-year-old won Sydney on Saturday beating veteran Andreas Seppi 7-5, 7-6 (5). The final lasted one hour and 15 minutes.
After Barty shot out of the blocks in the first set and led the deciding set 3-0, world No.8 Kvitova fought back time and time again in the 2hr 19min classic while battling fatigue to claim her second Sydney crown. To finally be able to take that step further and get my first win, it's something that's really special in front of friends and family and on the courts I grew up.
It came after de Minaur's earlier 1hr 34min 6-3 6-2 victory over Gilles Simon, where he was barely challenged despite temperatures of more than 30 degrees. "What's more annoying is me having to play Monday at the Australian Open and not getting helped out as a fellow Aussie at your home slam", said the 27th seed.More news: Lion Air jet crash: Cockpit voice recorder found
'To come out and just be able to back it up, first match in the sun and then later on, it wasn't easy. I feel like I'm playing great tennis. "Fitness-wise, I felt like I could keep going, as well".