The newly re-signed Walkinshaw Andretti United driver secured his second win of the season - and 15th of his career - finishing more than 12 seconds ahead of Ford's Cameron Waters.

After qualifying eighth, Mostert capitalised on a dramatic first-lap at Hidden Valley on Saturday.

Shell V-Power driver Anton De Pasquale's pole position advantage immediately disappeared after he was caught up in a six-car smash.

Championship leader Shane van Gisbergen slipped past the Ford driver on turn one, which resulted in Scott Pye colliding with De Pasquale.

The pile-up also involved Mark Winterbottom, Todd Hazelwood Fabian Coulthard, bringing the safety car out for five laps.

"I lucked into coming out of turn one in third so I thought 'that's a good result' and hope the car's OK," Mostert said.

"I tracked along. I was pretty quick at the start. I was a little bit worried about that because when you get a quick race car at the start and think you might not be able to go the distance.

"I was pretty lucky. Normally we've all got magnets and find each other, but neither one of us (Waters) didn't come together.

"I was lucky I started in the fourth row so super pumped for the whole team."

Van Gisbergen, who has already won six races this season, appeared to be cruising towards extending his series lead.

But disaster struck for the New Zealander, suffering a calamitous first pit-stop that cost him 26 seconds and saw him drop back to 20th.

Winterbottom was also left heartbroken after starting the race in second, saying "this sport gives me the "s****s sometimes" following the chaos.

The Darwin Triple Crown continues on Sunday with two more 38-lap races.

DARWIN TRIPLE CROWN RACE ONE

1. Chaz Mostert (Holden)

2. Cameron Waters (Ford)

3. Nick Percat (Holden)

4. James Courtney (Ford)

5. Will Brown (Holden)

Australian Associated Press