Sergio Perez's father Antonio has fired a warning over Yuki Tsunoda's new challenge at Red Bull, suggesting his car will not be the same as teammate Max Verstappens.
The Mexican has often been forthright in his opinions, with Perez Jr having to distance himself from his father's comments in the past.
But with Verstappen losing another teammate in Liam Lawson - the New Zealander jettisoned after just two races as Perez's replacement - Perez Sr has levelled an accusation at the Milton Keynes-based outfit.
“What I’m going to tell you today is going to cause a stir,” said Perez Sr, speaking on the Spanish language Formula de 2 podcast.
“I can tell you that car one is not equal to car 11 [Perez's former car number].
“If you bring the driver of car 1 to car 11, car 11 does not pass Q1. If you take the driver of car 11 to car one, he would run better."
Tsunoda will make his Red Bull debut in front of his home fans at the Japanese Grand Prix and Perez Sr has insisted the team "cannot fail" the fans.
“It’s the car. They are not the same. I hope that I’m wrong, and that Yuki in Japan has the best car that Red Bull can give him.
“He is in the home of Honda. It is the most important sponsor. He has to bring out his pride. They cannot fail the Japanese fans.
“They have to give Yuki the best weapons so that he can go out and fight. He has to have a very similar car.”