The #10 Chevrolet Camaro driver clocked a 1:30.535s ahead of Walkinshaw Andretti United’s Ryan Wood, whose 1:30.723s put him 0.187s in arrears of Percat.

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Matt Payne was third for Grove Racing ahead of Team 18 newcomer Anton De Pasquale and his teammate David Reynolds.

Jack Le Brocq (Erebus Motorsport), James Courtney (Blanchard Racing Team), Kai Allen (Grove Racing), Brodie Kostecki (Dick Johnson Racing), and Chaz Mostert (Walkinshaw Andretti United) completed the top 10.

Teams only have a limited supply of the new-for-2025 Dunlop tyres available for the test, leaving uncertainty over the true picture.

“Everyone is just running through probably a range of things. Obviously, we’ve got a lot of new stuff to go through,” said Will Davison at the break, who was 11th.

“It’s been a really interesting morning. I’m sure some people have run on the new-for-2025 tyre, some haven’t. We don’t get too many of them.

“Obviously, we’re racing on it this weekend, but we’ve only got a couple of sets to play with today. Just playing around, first time working with Brodie [Kostecki] and George [Commins] and Tom [Moore] in anger, which has been cool.

“Some really interesting feedback from Brodie. I’ve enjoyed the morning. We’re not too worried. We haven’t had any major hitouts yet, but the car feels quite different to what I’m used to – but quite nice. There are some good tendencies, so I’m having fun.”

The morning’s session was punctuated by Aaron Love crashing his Blanchard Racing Team Ford Mustang at Turn 2. The session was otherwise incident-free.

Triple Eight Race Engineering’s Broc Feeney clocked the most laps of any driver with 64 in his Camaro. He wound up 18th by lunch time just one place behind teammate Will Brown.

“It’s been good. There are a lot of clouds around, so it’s changing quite a lot over the day and obviously tyre sets, so at some points of the day, I felt like I was on fire and then you go back out and you’re like ‘Oh, maybe not’,” said Feeney.

“It’s very up and down. I think it’s all good. We’re getting through our program. I think this afternoon we’re going to see [quicker times].

“I think everyone has got the new model tyres to run. I’m not sure if anyone has run them yet, but I think for this afternoon you’re probably going to get an understanding in that last 10, 15 minutes where everyone is at.”

Matt Stone Racing’s morning wasn’t entirely trouble-free. Cameron Hill spent more than an hour in the pit lane after a battery fire.

Across the 25-car field, 2.6 seconds covered the grid with PremiAir Racing’s James Golding a distant last place, 0.7s away from Tickford Racing’s Thomas Randle in 24th.

Results: Repco Supercars Championship pre-season test, Sydney Motorsport Park (morning)