De Minaur will next face and Frenchman Gilles Simon, who beat Australia's John Millman 7-5 3-6 7-6 (7-3) in Thursday's late quarter-final match.
De Minaur was drawn on the bottom half of the schedule, the side of which all matches are set for Monday.
Petra Kvitova outlasted Ashleigh Barty in a final-set tiebreak to win the Sydney International for the second time on Saturday.
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.
In the first, Alex dropped his serve immediately before breaking back in the 6th game (3-all); in the second set was broken again in the 7th game (3-4), but then he leveled immediately after (4-4).
The 34-year-old Seppi, playing in his first decider in more than three years, hasn't won a tournament since 2012.
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.
Chris Pratt announces engagement to Arnold Shwarzenegger’s daughter Katherine. Check out pic
The couple was first spotted together at a picnic on Father's Day , followed by several dates around Los Angeles . Despite their divorce, it seems the two remain amicable. "She fits in really well with them and vice versa".
Jayme Closs’ aunt shares how teen spent her first day home
Barron County Sheriff Chris Fitzgerald has said he believes Patterson went to the property with the intention of taking Jayme. Then, on Thursday, a woman walking her dog in the town of Gordon, about an hour north of Barron, spotted Jayme on the street.
Trump threatens to 'devastate' Turkey's economy if they attack Kurds
The pullout was reportedly sparked after a phone conversation between Trump and Turkish President Recep Tayyip Erdogan. Washington , however, has continued to support the YPG, despite the USA listing the PKK as a terrorist organization.
Barty led the deciding set 3-0 before Kvitova began a comeback to win her 26th WTA title.
"I've just got to focus on doing the right things and looking after myself, listening to the great group of guys I've got around me and just keep doing what I'm doing, keep trying to improve every single day and getting out there and competing", de Minaur said.
Kenin now proceeds to Melbourne where she will play Russian qualifier Veronika Kudermetova in round one of the Australian Open.
"In a lot of tournaments you can look ahead and eventually you'll play one of the big guys".
"I'm very happy with my performance. And to be able to, in a way, to follow his footsteps and win (in Sydney) is definitely special". I mean, this is why I have done all the hard work in the preseason.
Moving the Australian's match to Tuesday would have meant that the victor between he and Sousa would have been forced to play two days straight in Melbourne.
"But I feel like I am hitting the ball well and certainly happy to come through in pretty straightforward fashion".