"The track was fast and quite tricky," said McDonald.
"It was pretty hairy getting into turn three. You had to drive it in straight.
"If you got it right, you were fast but, if you got it wrong, you were out the back door."
McDonald and crew chief Lee Rusher got their J&J chassis sorted with some last-minute changes.
"When we knew that we'd be on the front row for the feature, we decided to try some different things in the pole shuffle," said McDonald.
"It was a bit of a rush, we were still changing tyres on the infield during the pole shuffle and we only just made it."
McDonald was into lapped traffic early in the race and had lapped up to sixth place before the only caution of the race on lap 17, when national champ Rodney Wood (Tauranga) tangled with Paul Donovan.
In the remaining laps, McDonald edged away from Brindle again, with Eggleton and Tokoroa brothers James and Keaton Dahm the best of the Baypark drivers, taking fourth and fifth.
Former national champ Brent Emerson (Tauranga) won his first Super Saloon Car feature of the year, working his way past the battling Karl Hanlon and Russell Donovan to take the win.
The Saloon Cars raced with their more powerful counterparts and Steve Cowling pipped Brent McClymont for the class win.
In the Stock Cars, Scott Hayward won the feature race by a clear margin, while Ash Henstock raced to a narrow win over Sam Waddell in the Mini Stock feature race.