Jamie Whincup has snatched the fastest lap from Chaz Mostert in Practice 1 at the Tyrepower Tasmania SuperSprint by less than two hundredths of a second.

Mostert was quickest with a 50.7755s when the chequered flag came out, only for Whincup to then lap Symmons Plains International Raceway in 50.7564s in the #88 ZB Commodore.

The Red Bull Holden Racing Team driver does, however, face a post-session investigation regarding observation of yellow flags given that his fastest lap was set with Nick Percat beached in the gravel trap at the hairpin.

Shane van Gisbergen ended up third at 0.0983s away from his team-mate in the #97 Triple Eight ZB Commodore, with Scott McLaughlin (#17 Shell V-Power Mustang) fourth and David Reynolds (#9 Penrite ZB Commodore) fifth.

Whincup was fastest at the end of the first stints with a 51.0865s before van Gisbergen took over at halfway through the half-hour session with a 51.0738s.

The seven-time champion took the spot back when he moved the mark to a 50.9578s, only for van Gisbergen to usurp him moments later with a 50.8547s.

Mostert was outside the top half of the field with two minutes remaining but jumped initially to second and then to the lead in the final minute in the Supercheap Auto Mustang before being pipped by Whincup.

Percat (#8 Dunlop ZB Commodore) ran long with the chequered flag about to be shown and officials chose to hold fire on the red flag, although the Brad Jones Racing driver is himself also under investigation given that he piled into the gravel trap with Lee Holdsworth (#5 The Bottle-O Mustang) sitting on the apron having already made an error of his own.

They were not the only ones to leave the track at that corner, with Fabian Coulthard and Whincup having spins there and the BJR entries of Tim Slade and Macauley Jones missing the turn-in during the session.

Whincup said there was room for improvement in his car despite being fastest.

“The car’s okay, it’s reasonable,” he said.

“It’s not as nice as we’d certainly like, so we’ll do a bit of work in between P1 (Practice 1) and P2 (Practice 2) to try and improve it.

“I think everyone’s got a bit of a step to be made. Track’s quite quick. Only a couple of tenths off the practice record. On green tyres I think that could be in threat.”

McLaughlin, who reported that he would be ‘lying’ if he could discern a change due to the centre of gravity adjustments, was confident with his team’s progress despite a problem with shift lights.

“Straight away I said this has been not an amazing track for us, so I felt that was the strongest we’ve rolled out,” he reasoned.

“I felt really good straight away. Just a dash issue probably hurt us at the end there. When you’re not shifting right and all that sort of stuff, it does make a difference. Especially a place like this where it’s miniscule.”

Despite his error, Holdsworth had already done enough to put himself sixth fastest, ahead of Will Davison (Milwaukee Mustang), Scott Pye (Mobil 1 Mega ZB Commodore), Coulthard (DJR Team Penske Mustang), and Anton De Pasquale (Erebus ZB Commodore).

Wildcard Jack Smith led the BJR contingent in 15th in the SCT Logistics ZB Commodore, while no additional drivers took part.

Practice 2 (30 minutes), which sets the starting order for the first knockout Armor All Qualifying process of 2019, starts at 1420 local time/AEDT.

Results: Practice 1