Jamie Whincup quickest in V8s practice

For all but the final few seconds of Friday practice, Jamie Whincup looked more like an L-plater struggling to deal with his dad's car than the V8 Supercar champion.

Then he showed exactly why he is the dominant driver in the sport, producing a flying lap under duress in the dying seconds for the fastest time ahead of the weekend's Clipsal 500 in Adelaide.

Whincup's session was, by his lofty standards, shaping as a nightmare.

He started by losing control of his Holden and firing down an escape road, then copped a black flag for kerb-hopping midway through, before an embarrassing late session spin.

Add some new tyres and time pressure and the Team Vodafone driver once more donned his cape - fast becoming more like a cloak of invincibility with every V8 Supercar race.

"I had a really tough session to be honest," Whincup said after clocking a fastest lap of one minute 21.3729 seconds around the street circuit.

"It was a tough car to drive, I had no confidence in it whatsoever, then we made a few changes.

"I'm not happy and smiling at the moment. We've got a bit of work to do."

Unbeaten in the first four races of the season, it's the closest Whincup has come to missing a beat in his switch from the Ford, in which he won the past two championships, to an unfamiliar Holden.

He will have the chance to further extend his points lead when qualifying and the first of two 250km races are held on Saturday after edging out Ford's surprise packet Shane Van Gisbergen and Holden's Paul Dumbrell in practice.

Holden Racing Team's Garth Tander was sixth fastest despite keeping his best tyres in the locker.

But his teammate Will Davison struggled and was 21st as the HRT duo attempt to salvage their season following a disastrous showing in the Middle East last month.

Last year's runner-up Davison is languishing 13th in the standings, while Tander is even worse off in 22nd spot.

Meanwhile, Queensland driver Chris Wootton walked away unhurt from a spectacular crash in the Mini Challenge support category on Friday.

Wootton, 21, rolled his Mini three times at high speed and crashed into a concrete wall during qualifying.

While his car was a write-off, Wootton was able to walk back to the pits and was cleared of any injury.

- AAP