On a day where the temperature soared past 38 degrees, the racing was hotter still.
With five laps to go of the second race, Courtney took damage after cutting the barrier at turn one too fine, providing a most dramatic ending.
A last-lap wobble around the fastest turn at the circuit sent Courtney sideways but he held on in tremendous style, celebrating with his 'Frank the Tank' dance on top of the car.
"It was an amazing battle, shows why he's such a champion," Courtney said of Whincup. "I've been wheel-to-wheel with him all day which has been fantastic. It definitely was a fight at the end there. Old mate probably had a bit of a better car than we did we had to work hard to keep him behind us."
The first race lacked quite as much excitement, with Whincup leaping from the grid to overtake surprise pole-winner Scott Pye. Courtney shadowed him home but never mounted a serious challenge to his lead as Pye managed just 12th after a pit-lane bungle cost him several places.
Holden has won every race at the Clipsal 500 since the changeover to car of the future in 2013, with Holden drivers having won 12 of the last 13 Clipsal races since 2010.
- AAP