Lucas Dumbrell Motorsports Nick Percat has won the Clipsal 500 title following an extraordinary and highly gripping rain soaked V8 Supercars encounter at Adelaide.

Very rarely has a race been won under such dramatic and confusing circumstances as a mid-race suspension, necessitated by the vicious monsoon, shortened the afternoon by 30 laps.

With the threat of the result being declared on lap 42, the issue of the fuel drop regulation quickly became apparent.

The ruling stipulates that each car must take on a minimum of 140 litres of fuel, even if the race has to be shortened. That handed the impetus to the runners who bundled into the pit-lane before the final safety car phase.

LDM and Percat read the situation to perfection and subsequently took over the lead of the race when the remaining runners ahead pitted for fuel on the final lap.

Volvo's Scott McLaughlin and Triple Eight's Craig Lowndes both had track position ahead of Percat with the end in sight, but neither of the pair had taken on the required amount of fuel.

Percat has previously won the Bathurst 1000 alongside Garth Tander but today's victory marks his first solo V8 Supercars triumph in his career.

The afternoon took a dramatic twist even before the field could take the green flag lap as a freak band of torrential rain caused hysteria up and down the grid, resulting in a delayed start and hurried wet weather set up tweaks.

Reigning champion Mark Winterbottom bore the brunt of the confusion after electing not to swap to wet rubber before the parade lap had started. A huge moment for the Prodrive man at turn eight forced Winterbottom to relinquish his starting slot and pit for wets.

Such was the intensity of the rain shower, the race eventually got underway under safety car conditions, allowing for much of field to duck into the pit-lane and change their fuel strategy.

But that sparked further controversy as some teams, who didn't bring their driver's in for fuel, were under the illusion that the race hadn't officially begun.

Lap six marked the start of the race in anger. Pole-man Fabian Coulthard led the early running but amid the treacherous and chaotic conditions, James Courtney, Shane Van Gisbergen and Craig Lowndes scythed their way to the front.

While Lowndes was going well at the front, the same couldn't be said for his Red Bull team mate Jamie Whincup, who unceremoniously dropped down the field, courtesy of contact with HRT's Garth Tander.

Just as the race at the front was settling into some sort of rhythm on the drying track, Van Gisbergen ploughed into Courtney, promoting Lowndes into the lead.

All of that coincided with field crossing over to slick tyres, where Courtney amazingly re-emerged as the race leader but Lowndes quickly reasserted his authority and moved back past the HRT Commodore on the entry to turn eight.

But the rain returned om lap 28, creating yet more anxiety and frenzy, resulting in Chaz Mostert - who was running in the lead group at the time - slamming into the wall and bringing out the safety car at turn eight.

Courtney was the first driver to blink for wets but in doing so - just as David Coulthard had managed during the 1995 Australian Grand Prix - the HRT runner ran out of grip went straight into the wall on pit-entry.

The 2010-champion was able to continue but lost precious seconds whilst reversing away from the incident.

Rick Kelly emerged as the race leader when the safety peeled back into the pits but Courtney was back in the lead before the end of the lap, thanks to another pocket of rain wreaking havoc on the back end of the circuit.

That pocket of weather intensified as Courtney became the latest driver to fall on his sword thanks to yet another tropical storm engulfing the track - causing the HRT pilot to spear into the infamous turn eight wall.

The safety car swiftly followed in a bid to neutralise any further danger in the monsoon conditions but with no apparent let up of the biblical rainfall, the race officials placed the race under suspension on lap 42.

Mercifully, a break in the weather allowed the race to resume - albeit for only a further six laps - with Scott McLaughlin now inheriting the lead ahead of the TeamVortex Commodore of Lowndes.

However, the order behind the safety car was subject to massive change according to the fuel drop ruling, stipulating each car must obtain 140 litres of fuel at a given time.

With the seconds ticking down, McLaughlin and Lowndes juked it out for the lead but with the fuel situation far from clear the leading duo pitted on the final lap.

Sensationally, that left Lucas Dumbrell Motorsport's Nick Percat in the box seat for an unlikely and hugely popular win, having complied with the fuel drop ruling.

DJR Team Penske's Coulthard followed Percat home but the Ford runner was also caught out by the rules, meaning Michael Caruso and Holden's Tander complete the podium based on the fuel drop regulation.

Caruso and Tander come away from the weekend's action sitting first and second in the early title race while, narrowly ahead of Triple Eight's Whincup.