Whincup enjoyed a perfect day's racing, claiming a fourth-straight title with a victory in Saturday's second 100 kilometre race.But on Sunday, the Red Bull man eased to fourth place after starting on pole.
Slipping down the order, he instead enjoyed a Sunday drive and finished behind third-placed Mark Winterbottom.
Front-rowers McLaughlin and Whincup went side-by-side around the opening bends, with Tander lurking just behind.
The young Volvo driver held his nerve to emerge in front around turn two, with Tander using track position to also pass the provisional champion.
Along with Mark Winterbottom, the quartet formed a pack that would lead the field throughout.
Tander stole the lead when his first pit stop was quicker than McLaughlin, but a crash shortly after threatened the established order.
David Wall skidded through the gravel and out of the race on lap 14, bringing about the safety car and a quick change in strategy.
Every car in the field went into pit lane, creating chaos with double-stacking and a few bumps in pit lane.Tander again led the field out, with Winterbottom sneaking by Whincup in the frenzy.
The Holden Racing Team man held firm through the final 30 laps of the race, as McLaughlin sniffed for vulnerabilities around the coastal circuit.
His final chance appeared to have been lost with three laps remaining as a braking error cost the 21-year-old crucial time.
But the Volvo man was not to be denied, handed a shock win with around 100 metres to remain.
