Nissan Motorsport's strong start to the season came to a dramatic halt at Symmons Plains, where its Altimas were comprehensively out-gunned by their opposition in race trim.
Drivers Michael Caruso, Rick Kelly, Todd Kelly and James Moffat finished 19th through 22nd in Sunday's 200km Race 6.
With the race having run free of Safety Car periods, all four Altimas greeted the chequered flag a lap adrift of Craig Lowndes' winning Holden.
The team had headed to Tasmania off the back of a pole position and weekend podium for Michael Caruso at Albert Park.
Caruso finished 21st and 16th in Saturday's two 100km Symmons heats and, lining up 12th on Sunday, had expected to benefit from the longer format.
“I thought we'd move forward, but we didn't, and it's quite embarrassing,” he said.
“The performance of all four cars was not acceptable.
“We got our pants kicked and it's important that we get to work straight away and have a serious look at ourselves.”
Team owner/driver Todd Kelly, whose weekend included a high of eighth in Race 5 qualifying, echoed Caruso's frustration.
“We need to go and have a good hard look at ourselves after this weekend, the performance we had was pretty clear, with all four cars finishing nose to tail,” he said.
“We just didn't have the pace, and a lot of work needs to be done.
“We've got a lot of work to do before Winton, it's going to be a busy few days.”
Brother Rick Kelly fourth to 11th in the points standings across the weekend thanks to a horror run that included a brake failure in Race 4 and being punted off the road by Chaz Mostert in Race 5.
Although admitting that the poor Symmons performance had been about far more than simply a straightline speed deficit, Kelly is optimistic of a competitive showing at Winton next weekend.
“We haven't quite got the straight line speed we need, but we didn't have the setup here,” he said.
“We go to tracks as a team where we are extremely strong, and we go to tracks where we are weaker, I think a lot of that is down to the new generation car.
“It's good to get this one out of the way early in the season. It's a bad track for us, and now we head to the best track for us at Winton.
“We'll have a look at what we need to do for next year at Symmons Plains, but we are definitely excited for the tracks coming up after Winton where we will be strong.”
Moffat and Caruso took a one-two finish on Saturday at Winton last year.