Whincup has Supercars day to forget at QR

Holden ace Jamie Whincup admits an error-riddled day at Queensland Raceway has undone months of work in the Supercars championship.

Jamie Whincup says a day of errors in Ipswich has undone months of work in his Supercars title hunt. (AAP)

Supercars ace Jamie Whincup fears a Saturday shocker at Queensland Raceway has undone months of hard graft by his Red Bull Racing team.

The Holden star finished a forgettable 20th in the 120km event opener at Ipswich, a result compounded by championship rival Scott McLaughlin storming to his sixth win of the season.

Whincup, starting the day just six points behind the DJR Team Penske driver, is 111 points adrift of the the New Zealander. He knows the ground he had made up earlier this month with his first win of the year in Townsville has been instantly gifted back.

"We've ground it out over the past three months and got some good points and pretty much threw it all away today," Whincup told AAP.

Whincup, whose practice run on Friday suffered a hiccup when he failed to complete a clean lap on green tyres, made a crucial error in qualifying when he made contact with James Moffat in the pitlane.

After qualifying ninth, stewards handed him a five-position penalty for the incident, forcing him to start from the middle of the field in 14th.

Whincup began cleanly but a sloppy pitstop forced him down the field and compounded a day when nothing went right for the six-time drivers' champion.

"One to forget - poor qually, docked five spots and then something wrong in the pit stop and not much pace in the race. Whatever could go wrong, did go wrong," he said.

"We've had plenty of mistakes this weekend. Not good, not proud of them but that's the way it goes sometimes."