The 26-year-old won the Repco Supercars Championship for the first time for both himself and Erebus Motorsport, with his margin over Shane van Gisbergen blowing out to 323 points in the final race of the season.
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“It's truly an honour,” he said.
“Honestly, I wasn't expecting it at all.
“It was quite funny; we were at lunch earlier and we're starting to develop a great relationship between us all, but when those helmets go on, those relationships seem to delete themselves.
“But yeah, it's truly an honour to receive that trophy and to be voted by your peers is just awesome.
“It's a pretty cool feeling to be collecting both trophies and something I'll cherish forever.”
Nevertheless, Kostecki was keen to reiterate that his triumph, and Erebus's team's championship title, was a product of the effort of dozens of people in the background.
“It's something that means a lot to my team,” he remarked.
“Obviously, winning the drivers' championship is something I've always wanted to do and, honestly, four years ago, I didn't even know that I'd even get to this stage [of being] a full-time driver.
“But, to win the teams' championship as well, and see all the reaction on my team's faces is something that I'll never forget.
“Our sport's pretty funny at times; it seems like we're the ones in front of the cameras all the time, but there's 20 or 30 people behind the scenes that are the ones putting in all the effort.
“To be able to deliver the team those trophies and see the smiles on their faces is something that I'll never forget.”
Walkinshaw Andretti United's Chaz Mostert, who ended the year as the top Ford driver in fourth in the championship, scored the other big honour which was announced at the gala, namely the Barry Sheene Medal.