DJR Team Penske have fired back at Red Bull Racing's challenge, with Supercars leader Fabian Coulthard and teammate Scott McLaughlin scoring a one-two finish in Darwin.
Saturday's win extended Coulthard's lead in the overall standings to 34 points, while McLaughlin narrowed the gap on second-placed RBR driver Jamie Whincup to six.
It was Coulthard's first victory at Hidden Valley Raceway and his third for the season.
Whincup improved from ninth on the grid to finish fourth, but was denied a top-three finish by fellow Holden driver Nick Percat, who scored his first podium since joining Brad Jones Racing.
The win capped a big week for Coulthard, who announced he and partner Becky Lamb were expecting twins later in the year.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"This is massive. It's going to be a big year so, hopefully, we can finish it off in the correct style," Coulthard said.
Pole-sitter Rick Kelly's afternoon ended in disaster when his steering locked and he ploughed into a wall during a dramatic 18th lap.
With the safety car on the track, Coulthard was able to capitalise on being the first driver in the pits and didn't look back after racing resumed on the 23rd lap.
"For us, the smartest result is to get a one-two finish for the team," Coulthard said.
"We drove our race to getting a one-two. Whatever the order was, it didn't matter but I'm happy to get the win."
Moments before Kelly's crash, defending series champion Shane Van Gisbergen had a right-rear tyre failure, all but dashing his chances of back-to-back race wins.
His day went from bad to worse when he made contact with Garth Tander with three laps remaining, preventing him finishing.
After starting the race 37 points adrift, Van Gisbergen sits 87 behind Coulthard.
"You never want to get points for free, but we'll take them," Coulthard said.
"But it's such a long year, we're all going to have a bad run at some point - that's inevitable. You've just got to minimise the bad days."
McLaughlin was able to recover after dropping to sixth on the second lap when making a failed attempt to pass Kelly, a self-described "brain-fart" from the flying Kiwi.
He also stalled exiting the pits and was comfortably beaten to the first turn by Kelly after starting alongside pole.
"At the end of the day, we came back and that was probably the main thing," McLaughlin said.
"I need to work on my launches and we'll be OK."
Sunday's 70-lap race kicks off at 3:00pm.
