With four races remaining, Norris leads Piastri by just a single point in the standings after overturning a deficit of more than 30 points since the summer break.

Ecclestone, the former F1 boss, has suggested that growing internal tensions — and possible favouritism — are weighing on the 24-year-old.

“You can tell Piastri is upset and tired of them, and the discussions about them are getting on his nerves,” Ecclestone told sport.de.

“The pressure is constantly increasing, and Piastri is frustrated that he can no longer win races so easily and that Norris is clearly being favoured within the team.”

The 95-year-old said it “looks” as though McLaren have favoured Norris in the second half of the season, despite Piastri appearing “clearly faster” earlier in the year.

Ecclestone claimed the team had “more often slowed down the Australian using various methods”, though he did not provide specific examples.

Earlier in the season, Ecclestone had backed Piastri to win the championship, but now believed “something’s holding him back.”

“When the season started, I thought our Australian driver would be world champion,” he said.

“I thought he would win easily but something’s holding him back. I don’t know what it is. I don’t know if it’s McLaren holding him back or what.

“There was a bit of a problem inside the team I understand where it looked very much they were favouring the British driver.”

Ecclestone added that he believed part of the team’s preference stemmed from Norris’ stronger public profile.

“McLaren prefers the English driver Norris,” he said.

“He has more star power and marketing qualities for them, more camera presence and public exposure.

“That’s why it’s probably better for McLaren.”

Ecclestone also suggested that Norris’ comfort in the spotlight also played a role in McLaren’s preference.

“I think he would fall into the star quality more,” he said.

“He likes the TV, he likes the camera, he likes whatever. I suspect the journalists [like him].

“I suppose that’s better for McLaren.”

Despite McLaren’s recent success, Ecclestone still tipped Max Verstappen to snatch the title away from both.

“I think Max will win and do it again!” he said.

“He has that special something, that extraordinary quality. And the next race is Brazil — the weather is changeable, with rain too. Verstappen will do well there.

“Verstappen is special, the best racer, not a politician, but a real racing driver.”