McLaren's Lando Norris said he would lose respect for Max Verstappen if the Red Bull driver did not apologise for a collision that wrecked their Austrian Grand Prix on Sunday.
The pair are friends off-track but fierce rivals on Formula One race weekends and that boiled over at Spielberg's Red Bull Ring as they fought for the lead.
Stewards ruled triple world champion Verstappen was predominantly at fault for causing the collision and handed him a 10 second penalty, which had no impact on his result, as well as two penalty points.
Verstappen, who dropped from first to fifth but now leads Norris by 81 points after 11 races, declared the penalty ridiculous and was backed up by Red Bull team boss Christian Horner.
"He (Norris) didn’t behave correctly there Max. Desperately unlucky, especially here, but you did your very best," he said over the team radio.
A disappointed Norris, who retired with a puncture and car damage, said it was a tough one to take and accused Verstappen of being reckless and desperate in his driving.
"It depends what he says. If he says he did nothing wrong, then I lose a lot of respect for that," he told Sky Sports television when asked if their relationship would change.
McLaren boss Andrea Stella suggested Verstappen's behaviour, and moving while braking, was the result of the sport's rules being inadequately enforced years ago.
"The problem behind it is that if you don’t address these things honestly, they will come back," the Italian said.
"They have come back today because they were not addressed properly in the past when there was some fights with Lewis (Hamilton in 2021) that needed to be punished in a harsher way."
The incident gifted the Austrian Grand Prix to Mercedes' George Russell with Oscar Piastri finishing second for McLaren, 1.906 seconds behind, and Ferrari's Carlos Sainz taking third.
Russell's win was a first for once-dominant Mercedes since November 2022, when Russell also triumphed in Brazil 33 races ago, and only the second of the Briton's Formula One career.