The race started in dark, foggy conditions, race control happy to let it go green after a handful of laps behind the safety car.
Among those critical of the conditions was Chaz Mostert, who led the first stint in the pole-winning #65 Melbourne Performance Centre Audi.
He and Kelvin van der Linde (#74 MPC Audi) ran nose-to-tail until the 45-minute mark when the safety car was called to retrieve a crashed MARC Car from the top of the Mountain.
The two lead Audis pitted behind the safety car and handed over to their respective Am drivers, Liam Talbot and Brad Schumacher.
Most of the field pitted during that caution, some leaving Pros in the car and some following the lead Audis and putting Ams in despite the tough conditions.
That mismatch saw the order change once the race went green again, Broc Feeney (#888 Triple Eight Mercedes) charging to the front as the best-placed Pro at the restart.
Talbot initially dropped back to fourth before losing more time when he was hit by Tony D'Alberto (#6 Wall Racing Lamborghini) at Forrest's Elbow.
Schumacher, meanwhile, sunk back to 12th during a difficult few laps that included an off at The Chase.
Right on the 90 minute mark the safety car appeared again, this time to retrieve the #4 Grove Racing Porsche which was left stranded in the Turn 1 gravel trap by Brenton Grove.
That prompted another wave of stops as a burst of rain prompted a scramble for wet weather tyres.
The timing of the stops played into the hands of the #65 Audi, which wound up in the lead with Fraser Ross now at the wheel.
However Ross was happy to let several Pros through shortly after the restart, Nick Percat taking over the lead in the #17 Team BRM Audi.
The green running was short-lived, the safety car once again called again several laps later when the sole KTM X-Bow in the field ground to a halt on Conrod Straight.
Percat continued to lead at the restart shortly before the two-and-a-half hour mark ahead of D'Alberto and Garth Walden (#45 RAM Motorsport Mercedes), who didn't pit during the caution.
When the race went green it was fifth-placed Ricardo Feller in the #777 MPC Audi that went on a tear, the Swiss ace quickly charging into the lead.
By that point that car had already served a drive-through penalty for a bizarre incident during the first safety car when Yasser Shahin passed two cars after serving a stop.
A little after the 2.5-hour mark Feller opted to make his third stop, which dumped him back in the field and handed the lead back to Percat.
The Supercars star continued to lead until the three-hour mark, his margin at that point around 17s seconds.
The #9 MPC Audi is currently second with Lee Holdsworth at the wheel while Feller has worked his way back up to third.
Next in line is the #74, #47 #24 and #65 MPC Audis ahead of Shane van Gisbergen in the #888 Mercedes.
The #19 Nineteen Mercedes, meanwhile, is out of the race after Jack Perkins hit the wall at The Chase while on an out-lap during the second safety car period.
