Standing just two points away from his first career final, De Minaur committed a string of errors, including a double fault to concede a set point to Harrison, allowing the world number 47 back into the match.
Kyrgios has often struggled to produce his best tennis at the grand slams, but he goes into the Australian Open having made a strong start to the season, including a semi-final victory over world No 3 Grigor Dimitrov.
One thing that did concern Kyrgios during the Brisbane final was being denied a medical timeout to reaffix the strapping on his knee, a decision he questioned at a change of ends.
"For me it is important to pick the right tournaments and be invested in the ones I pick and, if I do the right scheduling, I think it is more than possible to finish in the top 10 - top five if I am playing like this".
He admits Bernard Tomic's absence is "strange" but Australian No.1 Nick Kyrgios likes what he sees from compatriot Alex De Minaur after joining the teenager in the Brisbane International semi-finals.More news: Drone attack on Russian Federation bases in Syria 'came from Idlib'
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Kyrgios only got better from that point on though, a 17th ace sealing the victory in 1 hour and 13 minutes as he appeared largely untroubled in his movement. "I love playing in front of you guys (Brisbane spectators) even though sometimes it might not seem like I do", said Kyrgios, who said he liked the idea of being on the Brisbane champions list with Lleyton Hewitt, the 2014 victor.
"He played a pretty solid first set, I played a pretty loose game to get broken", Kyrgios said.
Asked if he could give an insight on Tomic, Kyrgios said: "I have no idea".
The 31-year-old, who won 22 national titles in rowing, finished third in his debut last year and said it had been a battle in hard conditions.
However, Harrison stepped up the pressure and reeled off the next four points to take the set and level the match. Winning easily, he takes the match over Harrison 6-4, 6-2.
With such an improved performance, he certainly puts himself in the running for a first Australian Open.