Dr Helmut Marko has described his Mercedes counterpart Toto Wolff as an "unworthy loser" after the incredible and controversial 2021 season finale in Abu Dhabi.
Amid Red Bull's wild initial celebrations to mark Max Verstappen's shock title win, Mercedes was busily lodging two protests about the highly contentious final laps.
"It was unworthy that the decision was delayed like that," Marko told Osterreich newspaper.
"But that says everything about the attitude of an unworthy loser," the top Red Bull official added.
In many ways, it is a shame but also fitting that such an intense and close championship battle between Verstappen and Lewis Hamilton will now enter a new phase - Mercedes' appeal.
But Red Bull noted that it was an in-house Mercedes lawyer who presented the case to the stewards late on Sunday.
"We're a racing team," a team spokesman for Red Bull said. "We don't have any lawyers with us.
"We didn't come here to protest."
However, even 78-year-old Marko admits that Formula 1 has some thinking to do over the winter period.
"The whole system needs to be rethought," he said.
"It needs consistency. Decisions cannot be interpreted this way and then that way. The rules have to be simplified and the premise must be 'Let's race'."
But Marko stops short of joining those who are calling for race director Michael Masi to be ousted.
"That's not our job," said the Austrian. "But after so many mistakes and questionable decisions, there is certainly a need for action.
"We have a new (FIA) president coming and that's where he should start."
