In a slap in the face to Jamie Whincup's quest for Mount Panorama redemption, Peter Brock's brother has questioned the Holden gun's mental strength ahead of Sunday's Bathurst 1000.
And in another swipe, Phil Brock has also accused Whincup's team boss Roland Dane of providing preferential treatment to the four-time Bathurst champion.
Phil Brock will present the winner's trophy named in his famous sibling's honour on Sunday to mark the 10th anniversary of the record nine-time Bathurst champion's death.
Whincup on Thursday looked like the man most likely to accept the Peter Brock Trophy with co-driver Paul Dumbrell after their Holden dominated day one of practice.
But Brock wondered whether Whincup would have the mental fortitude to bounce back and claim a fifth Great Race after his recent troubles.
The record six-time Supercars champion has had plenty of Bathurst success but he has not tasted victory since 2012 after the team were left to rue his last two campaigns on the mountain.
Whincup last year sensationally ignored team orders to pit before passing a safety car, relegating him from second to the back of the field to eventually finish 18th.
And in 2014, the Holden gun also defied a team directive and ran out of fuel on the 161st and final lap while leading the Great Race.
Brock did not rule out another Whincup brain explosion on Sunday.
"Don't get me wrong - I think Jamie is a very good driver," Brock told AAP.
"But from what I have seen, he can mentally go off the boil at times.
"He can get too fired up then makes a bad call."
He might rate Whincup's ability but Brock remarkably hinted the Holden driver also enjoyed influence from boss Dane.
"I think (Whincup's Holden teammate) Shane van Gisbergen could win Bathurst for the first time this weekend," he said of the series-leading Kiwi.
"But if Roland gets his way, I think he will try and make sure Whincup wins.
"Roland obviously likes him.
"Nowadays, I think there are far too many ways a team manager can engineer things to create results."
For the record, Whincup reckoned he had no Bathurst regrets despite enduring two frustrating years on the mountain.
"There's no use looking back into the past," Whincup told AAP.
"I don't regret anything that happened.
"I felt I made the right call with the information I had.
"I will do the exact same thing this year and beyond."
Whincup might not be getting much love from Phil Brock but the Holden champion only has admiration for the man honoured this weekend, affectionately dubbed "King of the Mountain".
"I didn't know Peter but, of course, I respected him - he is the icon of our sport," Whincup said.
"Remembering him makes you want to do your best job, come Sunday."
Whincup - placed second in the series - has already impressed at Bathurst, his Holden topping the timesheets in each of Thursday's three practice sessions.
He left his best until last, clocking two minutes, 05.29 seconds ahead of Ford duo Fabian Coulthard and 2014 champion Chaz Mostert.
Nissan's James Moffat did not emerge in the final session after co-driver James Golding clipped the wall near Reid Park in the second practice.
Qualifying starts on Friday afternoon.
