James Courtney beat Scott McLaughlin to top spot in the opening Supercars practice session of the weekend at Phillip Island.
It was Holdens on top across the 40-minute session, Scott Pye leading the early running with a 1m31.465s set inside the first 10 minutes.
David Reynolds then went quickest with a 1m31.358s shortly afterwards, before Courtney jumped to the top with a 1m30.936s with 10 minutes of the session left to run.
With less than three minutes to go Courtney improved to a 1m30.646s, good enough to secure P1.
"It’s been great. We rolled out this morning and straight away the thing went up to the top," said Courtney.
"The platform feels really quite stable, quite consistent in these long, loaded corners. With that stability through the corners it gives us drivers a lot better idea of the grip level you’ve got, so then you can use all of it.
"In previous years here the cars have been really quite nervous. I couldn’t be happier at the moment.
"I don’t know what everyone else was doing, but our car feels good."
McLaughlin was second fastest, just 0.03s off Courtney, but it was hardly a trouble-free session for the Penske star. He fell victim to the tyre-killing nature of the Phillip Island layout, suffering a front-right failure midway through the session while on a race run.
"We were doing a race run and you want to find out where things are," said DJR Team Penske team principal Ryan Story.
"It wasn’t exactly the best set of tyres that we brought with us either. We know where that limit is now, by default, and we learnt a little bit there."
Shane van Gisbergen was third fastest, jumping from well outside the Top 10 with his final lap. Triple Eight teammate Craig Lowndes did likewise, settling into fourth with a late effort.
Cam Waters was the best of the Tickford Fords in fifth, ahead of Nick Percat and Pye, who was shuffled back to seventh.
Fabian Coulthard was eighth quickest, Reynolds ninth after never improving on that early lap, with Garth Tander rounding out the Top 10.
Todd Hazelwood was the surprise of the session with the 11th quickest time, while Rick Kelly was the best placed Nissan in 12th.
There were some big names outside the top half of the field, with points leader Jamie Whincup just 17th fastest. Chaz Mostert was even further back, finishing 19th after an off at Southern Loop early in the session.
|1||25||James Courtney||Holden Commodore ZB||1'30.6461|
|2||17||Scott McLaughlin||Ford Falcon FG X||1'30.6765||0.0304|
|3||97||Shane van Gisbergen||Holden Commodore ZB||1'30.7240||0.0779|
|4||888||Craig Lowndes||Holden Commodore ZB||1'30.7565||0.1104|
|5||6||Cameron Waters||Ford Falcon FG X||1'30.7798||0.1337|
|6||8||Nick Percat||Holden Commodore ZB||1'31.0308||0.3847|
|7||2||Scott Pye||Holden Commodore ZB||1'31.0386||0.3925|
|8||12||Fabian Coulthard||Ford Falcon FG X||1'31.2631||0.6170|
|9||9||David Reynolds||Holden Commodore ZB||1'31.3582||0.7121|
|10||33||Garth Tander||Holden Commodore ZB||1'31.3796||0.7335|
|11||35||Todd Hazelwood||Ford Falcon FG X||1'31.5911||0.9450|
|12||15||Rick Kelly||Nissan Altima||1'31.6025||0.9564|
|13||18||Lee Holdsworth||Holden Commodore ZB||1'31.6720||1.0259|
|14||78||Simona de Silvestro||Nissan Altima||1'31.6979||1.0518|
|15||230||Will Davison||Ford Falcon FG X||1'31.7027||1.0566|
|16||5||Mark Winterbottom||Ford Falcon FG X||1'31.7103||1.0642|
|17||1||Jamie Whincup||Holden Commodore ZB||1'31.7505||1.1044|
|18||99||Anton de Pasquale||Holden Commodore ZB||1'31.7641||1.1180|
|19||55||Chaz Mostert||Ford Falcon FG X||1'31.8199||1.1738|
|20||56||Richie Stanaway||Ford Falcon FG X||1'31.8880||1.2419|
|21||7||Andre Heimgartner||Nissan Altima||1'31.9420||1.2959|
|22||23||Michael Caruso||Nissan Altima||1'31.9484||1.3023|
|23||34||James Golding||Holden Commodore ZB||1'32.1606||1.5145|
|24||14||Tim Slade||Holden Commodore ZB||1'32.3757||1.7296|
|25||21||Tim Blanchard||Holden Commodore ZB||1'32.4100||1.7639|
|26||19||Jack Le Brocq||Holden Commodore ZB||1'32.5306||1.8845|