Max Verstappen's refusal to help Sergio Perez in his bid for second in the championship was reportedly based on frustrations that have been bubbling away for five months since May's Monaco Grand Prix.
According to two Dutch journalists well connected to the Verstappen camp, the two-time world champion believes Perez intentionally crashed at the end of qualifying of that event in order to line up ahead of him for the race that followed. Perez went on to win in Monaco, while Verstappen finished third.
Verstappen's refusal to follow what was a simple request to finish a race in seventh and not in sixth at Interlagos means Perez goes into the final race level on points with Ferrari's Charles Leclerc -- Red Bull is determined to secure a drivers' championship one-two for the first time in its history, but Verstappen's decision has complicated matters.
The incident provided a remarkable insight into Verstappen's character -- a petulant moment of defiance by a man who wrapped up the championship four races ago, winning a record number of races in one season with Red Bull's superb RB18 car in the process, over a perceived slight from 15 races ago.
It also raises big questions about Red Bull's driver harmony, which last year was a strength of the world championship winning team, going into 2023.
What exactly happened in Monaco?
The incident which appears to have caused it all is the third qualifying session for the Monte Carlo race. An important side note to everything here is that Monaco took place a week after Perez had moved over to let Verstappen win the Spanish Grand Prix, a team order he disagreed with, but obeyed. Perez was a man fired up that weekend.
In Q3, drivers usually get two attempts, one at the beginning of the session and one at the end, with time to change tyres in between. After the first runs in Monaco, Ferrari's Charles Leclerc and Carlos Sainz were first and second, with Perez third and Verstappen fourth.
At the start of the next qualifying runs, Perez spun coming through Portier, the right-hander before Monte Carlo's famous tunnel section, and hit the wall. That meant a red flag, which immediately neutralised the session and locked in the starting positions as they were.
Perez would turn third into first place on Sunday, timing an early pit-stop to perfection to jump the Ferrari drivers and win the race. Verstappen would spend a frustrating race as the third in a train of four cars on a circuit where overtaking is almost impossible. While he did not show much frustration that Sunday evening, it is clear that moment had a big impact on Verstappen.
The day after that Monaco race, Verstappen's father, Jos, had been very outspoken, writing a blog on his son's official website criticising the team.
"Red Bull achieved a good result, but at the same time exerted little influence to help Max to the front," Jos wrote at the time.
He added: "I think ten points from Max have been thrown away here. Especially with the two retirements we've had, we need every points. Don't forget that Ferrari currently has a better car, especially in qualifying."
In a recent interview with Dutch newspaper De Telegraaf's Erik van Haren, one of the best-connected journalists to the Verstappen camp, Jos was asked what he felt was the pivotal moment in his son's second title-winning campaign.
"For me the turning point was the race in Monaco," he said. "That weekend, when he got annoyed about how everything was going, [it] did something to him. After that, there was no measure of him anymore. I do know: If Max has had a disappointing race, then he is extra keen to make up for it."
These quotes appear to be quite cryptic when read with the knowledge of Verstappen's view of qualifying at that event.
Whether Perez did it intentionally or not is an open question. Side-by-side videos of his first and second Q3 laps in Monaco circulated on Sunday evening on social media do show a clear difference in Perez's throttle application on the latter attempt, but this in itself is open to different interpretations. While some suggested the difference was an intentional act to force his car into the barriers, it could just as easily be the sound of his rear wheels unexpectedly spinning up at that part of the circuit.
According to both Van Haren and ViaPlay's Tom Coronel, at the next race in Baku, Perez admitted to both Christian Horner and Helmut Marko that he had intentionally crashed. ESPN has been unable to confirm whether that admission ever took place.
On Sunday, shortly after a meeting with Perez, Horner and Marko to discuss what had happened on the final lap at Interlagos, Verstappen suggested in his TV interviews that an incident from earlier in the year contributed to his decision.
"Well, I have my reasons for that," Verstappen said. "We just discussed that, and I think it was better that we finally sat together and spoke about it, and just moved forward from here."
When asked by Rachel Brookes of Sky Sports F1 whether the incident he was referring to had been about Monaco, Verstappen smiled and said: "I'll let you work that out yourself."
When approached by ESPN, Red Bull denied that Monaco was mentioned during the postrace debrief in Sao Paulo, but did not offer an explanation as to what else Verstappen might have been referring to.
What happens next?
Perez's radio message immediately after the race spoke volumes about his mindset: "It shows who he really is."
Perez was clearly angry when he spoke to TV journalists immediately afterward.
To one Spanish-language broadcaster, he said: "I believe ... if he has two championships it is down to me."
That quote was clearly a stretch but highlighted just how wronged he felt in the immediate aftermath. He later revised that down to: "After all I've done for him, it's a bit disappointing to be honest. I have no idea. I'm really surprised."
Perez's stern defensive moves against Hamilton in Abu Dhabi last year earned him the nickname "Mexico's Minister of Defence," arguably helping keep Hamilton's lead just outside of the pit-stop time window he needed in case of a late safety car -- as it turned out, that was crucial to Verstappen being in a position to win the race and the title on the final lap.
Red Bull seemed happy the situation was resolved leaving Sao Paulo -- Horner said his drivers had shaken hands after that meeting -- but the question of whether Perez will obey any team orders in the future is an open one now, especially if the team faces a closer championship challenge in 2023 than it has for the majority of this year.
Although Red Bull has worked hard to deny suggestions that the team is built around Verstappen, the Dutchman appeared to lay down a clear marker on Sunday evening of where he sees his place relative to Perez.
When asked whether Verstappen thinks he is bigger than the team, Horner said: "No, we work as a team, we race as a team."
The talking point from Red Bull then became Verstappen's willingness to help Perez in Abu Dhabi, which begged the question why he had complicated the maths in the first place.
"If we go to Abu Dhabi and he needs the points, because they're tied, it's not the end of the world, it's all about who finishes ahead anyway. If he needs the help, I'll be there," Verstappen said.
"But it's good that we talked about it now and basically cleared everything that was there, why I didn't do it."
Horner added: "Our objective, our priority, is to see if we can get Checo second in the championship.
"Max has given it his commitment as well that we'll be doing the best we can to achieve that. It's a straight fight between Checo and Charles, and if Max can help in any way, he will do.
"We discussed it as a team, we discussed it behind closed doors. We'll discuss it in a larger group later. A bigger discussion will be why we were missing the pace today and this weekend. It's all dealt with above the table and we move on."
One smaller, but still fascinating, element to all this is the future of Daniel Ricciardo. ESPN understands the Australian is still in talks with Mercedes and Red Bull about a reserve driver role for 2023. There is no rush to make a decision, but one might be announced at the Abu Dhabi Grand Prix.
A return to Red Bull now might seem like the more sensible of those two options, as a further rift between Verstappen and Perez could open the door for Ricciardo to return to a race role in 2024. It's a two-way street, though, and the events of Sao Paulo might end up working against that option if Red Bull feels that adding a competitive third driver to the team's roster would further antagonise Perez.