Matt McLean has paced opening practice for Super2 and Super3 drivers at a sodden Sydney Motorsport Park.
The Eggleston Motorsport driver clocked a 1:40.784s to top the 50-minute session.
The hit-out was punctuated by two red flags, with passing showers making life tricky for the Dunlop Series field.
Click here for Practice 1 results
Drivers tip-toed around the circuit early on, with Triple Eight debutant Cameron Hill clocking a 1:46.069s.
Through 10 minutes, only seven drivers in the 33-strong field had set a representative lap time.
Grove Motorsport teen Matt Payne upped the pace as the circuit continued to dry, before Image Racing recruit Jay Hanson vaulted to the top on a 1:42.224s.
Hanson's teammate Jaylyn Robotham lowered the marker to a 1:41.682s, and again to a 1:40.886s.
That was set just as the red flag flew for the beached car of Paul Boschert at the Turn 8 hairpin.
Super3 runner Boschert couldn’t move his car from the slippery corner infield, triggering the first stoppage of the session.
Rain returned during the five-minute stoppage, but the circuit rapidly dried out again as the sun reemerged.
Several key names encountered minor offs in the opening minutes; notably, Tickford driver Zak Best bowled a wide at Turn 1.
Cameron Hill ended up third quickest on debut
Shortly afterwards, MW Motorsport recruit Angelo Mouzouris met the grass at Turn 2.
McLean set his time before the second red flag, with Garry Hill finding the Turn 1 tyre wall after sliding across the wet grass.
Hill ended up fifth of the Super3 winners, with McLean's Eggleston teammate Kai Allen quickest on a 1:43.263s.
Of Super2 notables, Declan Fraser wound up eighth ahead of Best and Mouzouris, with Elly Morrow 15th and Nash Morris 16th.
Cars will return to the circuit for Practice 2 at 4:40pm AEDT on Friday. CLICK HERE to view the race schedule.
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