Will Brown put Erebus Motorsport on top in official pre-season Supercars testing at Winton ahead of the 2021 campaign.
With a full rookie day under his belt already, Brown was able to hit the ground running for the final official pre-season test.
He jumped to the top of the times with 1m19.508s just an hour into the 8.5-hour test, that time leaving him a full half a second clear of the field.
Brown and enduro co-driver Jack Perkins also logged a total of 97 laps in what was a promising day for the Holden squad.
"It's always exciting to be quickest," said Brown.
"We're race car drivers, that's what you always want, you're never happy if you are second.
"We did put [green] tyres on at the start, but we're still quick running older [tyres] so I'm pretty happy with how the car is going."
Warm conditions meant the track was fastest in the morning, although there were some rare exceptions of late improvements.
One was Chaz Mostert, the Walkinshaw Andretti United ace jumping to second inside the last 90 minutes of running with a 1m20.035s.
That put Mostert just clear of Kelly Racing Grove newcomer David Reynolds, who set his best time on the eighth of his 80 laps.
Scott Pye was the best of the Team 18 cars in fourth ahead of Erebus driver Brodie Kostecki.
Cam Waters, expected to be a title contender this season, was just sixth fastest, but did set the milage pace with 135 laps.
Bryce Fullwood and Nick Percat were seventh and eighth fastest respectively, while James Courtney was ninth despite his #44 Tickford entry prompting a red flag midway through the day.
The car was in the hands of Tickford co-driver Thomas Randle at the time, a practice pitstop to blame for a loose wheel that left the car stranded with minor damage.
Tim Slade cut 113 laps on his way to 10th fastest for the new Blanchard Racing Team, followed by Brad Jones Racing pair Jack Smith and Macauley Jones.
Jack Le Brocq, Todd Hazelwood, Mark Winterbottom and Andre Heimgartner rounded out the field.