Jamie Whincup opened the Coates Hire Melbourne 400 by topping the times in the opening practice session at Albert Park.

The reigning Supercars champion posted a 1:55.40s effort on supersoft compound tyres with his final flying lap in the 30 minute session.

Whincup, on green tyres, proved to be 0.3s faster than Brad Jones Racing’s Nick Percat who was among group of drivers to improve late in the running.

“Just a slippy track, this AGP circuit,” said Whincup.

“I don’t think it’s been resurfaced for a long time, but the car’s there or thereabouts. We’re slowly chipping away (with) this next generation Commodore.”

Lee Holdsworth ended up third having set the initial pace with an effort on his first timed lap, which was good enough to remain in the top three.

James Courtney was fourth in the #25 Walkinshaw Andretti United Commodore, while Fabian Coulthard (Shell V-Power Racing) emerged as the top Ford in fifth.

Coulthard was running a new composite bonnet on his car after Supercars approved the use of new panels for Ford and Nissan teams prior to the session.

Scott Pye was sixth while the top 10 was completed by David Reynolds (Erebus Motorsport), Chaz Mostert (Tickford Racing), Garth Tander (Garry Rogers Motorsport) and Michael Caruso (Nissan Motorsport).

All four Nissan Altimas were running new composite roofs after receiving a green light from Supercars.

Meanwhile, Adelaide 500 winner Shane van Gisbergen was 17th fastest just behind Scott McLaughlin in the #17 Shell Ford.

Mark Winterbottom, equipped with a new lighter bonnet, ended the session last after his fastest lap, his only tour using supersofts, was scrubbed from the results due to a kerb strike.

The Ford driver fell foul of track limits rules at the Adelaide 500.

“He got a kerb strike on his one timed lap on soft tyres,” said Tickford boss Tim Edwards.

“(He was) Probably just in front of Chaz, so sixth or seventh or something like that.

“He only did one timed lap and he got a kerb strike, although it didn’t come up on the screen as a kerb strike. We had to ring someone to find out and they confirmed that.”

Supercars will return to the track for a second 30 minute practice session at 1440 local time/AEDT.

Results: Practice 1