Jayden Ojeda has blitzed the field in the opening Dunlop Series practice session at Mount Panorama.
The session was delayed after heavy fog descended on the mountain, with cars following the BP Ultimate Safety Car for two laps.
As the session went green, cars fought for track position and aimed to set quick times.
However, Ojeda left it until the very end, setting his 2:08.1463s best to put a margin on his rivals.
Broc Feeney started life with Triple Eight Race Engineering third overall, with Eggleston Motorsport recruit and karting prodigy Matthew McLean splitting the duo.
Ojeda's margin to McLean was a whopping 0.3440s, with Feeney a further 0.0077s in arrears.
McLean led through the opening half of the 40-minute session, with Ojeda, Angelo Mouzouris, Jordan Boys and Feeney filling the top five through 17 minutes.
An incident for Boys at the Chase triggered a red flag, with cars returning to the track with under eight minutes remaining.
Feeney rose to the top on his 11th lap with a 2:08.4980s, before Ojeda and McLean improved on their final runs to jump the #888 Commodore.
It was a mixed morning for MW Motorsport, with recruit Josh Fife spending the bulk of session in the garage with engine issues.
Boys remained fourth ahead of Tickford Racing's Zak Best and Mouzouris, with Tyler Everingham, Matt Chahda, Jaylyn Robotham and Declan Fraser rounding out the top 10.
Jon McCorkindale was the highest-placed runner in the Super3 class in 13th.
Second and final Dunlop Series practice will get underway at 3:10pm AEDT.