Shane van Gisbergen admitted “we suck” after qualifying 15th and 22nd for Race 29 and 30 at the OTR SuperSprint The Bend.
Qualifying at the Tailem Bend circuit was punctuated by a mistake in the second session, which saw the Red Bull Holden Racing Team run off the road at the penultimate corner.
Click here to have your say on the state of Australian motorsport and go into the draw to win a Kincrome Tool Armour Workshop valued at $11,999.
With time for a second flying lap, van Gisbergen crossed the line with two seconds to spare in the session, but didn't press on with a last-gasp effort.
His Sunday slump stood in stark contrast to his Saturday pace, which saw him qualify third and finish second in Race 28 behind Shell V-Power Racing Team driver McLaughlin.
The 31-year-old was left confused by the lack of qualifying speed.
“That's just where we are, unfortunately,” said van Gisbergen.
“We've detuned something. The car was so fast yesterday and I just get out there and I feel like I'm on ice.
“It was a pretty good lap and we're 22nd. It's weird.
“We've got no words man, we suck. I don't know. We need to get better.
“I've got no words, man. We're 22nd.”
The championship contender bounced back on Sunday, qualifying fourth and third for Race 29 and 30 respectively.
Race 29 of the Virgin Australia Supercars Championship starts at 11:50 local time/12:20 AEST.