Australia's Tom O’Halloran and Oceania MacKenzie earned places at next year's Olympics in Tokyo after respectively winning the men and women's contests at the International Federation of Sport Climbing (IFSC) Oceania Championships.
O'Halloran was the victor of a four-way battle in Sydney between compatriots Ben Abel, James Kassay and Thomas Farrell.
Farrell triumphed in the speed event, while Abel led the boulder and Farrell placed first in the lead stage.
The 28-year-old O'Halloran proved that consistency was key, however, finishing second in all three competitions to top the overall standings with eight points.
Abel was second on 15 with Kassay third on 18.
Combined is the discipline on the Tokyo 2020 programme, where sport climbing is due to make its Olympic debut.
"You only get one go in your life to try and be an Olympian," said O’Halloran.
"I had some pretty serious ups and down with my motivation.
"I nearly pulled out, because it was just too difficult.
"The training, the juggle with work and family life, missing out on time with my daughter and partner.
"The things that kept me going was 'What am I going to feel like the morning of the competition when I’m not there?'.
"I feel really proud of the work that I’ve put in, regardless of the result."
The 18-year-old MacKenzie dominated across all three events in the women's contest, finishing with a perfect score of one in the overall standings.
Her nearest opponents were fellow Australians Angie Scarth-Johnson and Ella Easton with 12 and 42 points respectively.
"It was very stressful, but I’m so happy," said Mackenzie.
"I was a little nervous warming up and getting all my stuff together, but once I started climbing I was like 'Okay, this is good!'.
"I had a very good time.
"Now we’ll get back into training, seeing where we can travel to next year to compete at a high level, doing a couple of world cups per discipline."
There are now 38 athletes who have qualified for Tokyo 2020, with the remaining two spots set to go to an athlete from host country Japan and one from tripartite commission invitation.
Climbing is set to make its Olympic debut at the Games, which are scheduled to take place from July 23 to August 8 after being postponed due to the COVID-19 pandemic.