The 15-year-old went into the last round at Murray Bridge in South Australia under-prepared, as participants were not allowed to do any testing prior to the event due to COVID-19 restrictions.

This, Costa's father Con said, meant they were "quite disadvantaged" as NSW drivers, but considering the 15-year-old's form leading in to the event, still confident about their chances.

"We didn't get to race on a track we could test, because there's a complete testing ban," Con said.

"Every corner's different, every straight is different, you have to test the temperature according to different tracks, so you have to have the kart set up with gearing and different axles and different seats.

"So we weren't as confident as normal, but we were hoping for the win and we knew nothing is impossible."

The impact of a lack of testing was clear from the start, as Costa struggled to find the same level of dominance he has shown throughout the year.

But with each race, he learned and his times steadily improved despite the dustiness of the track.

"We were a bit slow early, because I'm not as sharp as some of the professional teams, but luckily we came through," Con said.

"We won a race on Saturday afternoon, and would've won the pre-final on Sunday morning but I messed up the tyre pressure.

"He got a close second in that but then won the final in the afternoon."

Costa finished the final with a time of 15:03.146, nearly two tenths of a second ahead of Jake Rutkowski in second.

Though the effort was good enough to secure him victory in the last race of the weekend, Costa narrowly missed out on winning the Australian Championship to Leon Cordato, who finished in sixth but simply needed to avoid crashing to clinch the title.

It was a bitter pill to swallow for Costa, but his results throughout the year have been stellar and more than he or his father could have hoped for.

"It's fantastic, he's been very determined and focused," Con said.

"I believe he won on Sunday through pure determination, his ability to now evolve as a driver ... he's become quite a rounded driver. He's done very well."

Considering Costa's potential move to Formula 4 in 2022, this year has been the perfect lead-in as he eyes the European circuits.

"Other than Costa not clinching the Australian Championship in this category, I think it's the best possible build-up," Con said.

"He'll now endeavour to further his driving career, whether that be in the European Karting Championships, he has some opportunities there to investigate, or whether it's through the open-wheeler categories both in Britain and Italy where he also has opportunities, albeit quite difficult and challenging.

"It's just about the best possible buildup he could have had considering the lack of international travel, which affects competition."

Con also made a point of thanking the team at Wakefield Park, who he said have been "extremely supportive" of Costa. The young local has been allowed to complete some testing on the Wakefield track, which has been crucial throughout the COVID-19 lockdowns and border closures.

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