Departing Red Bull motorsport advisor Helmut Marko believes Max Verstappen would have won the 2025 world championship had former team principal Christian Horner left the team earlier in the season.
Red Bull confirmed last week that Marko will leave the team at the end of 2025 following a turbulent year in which Horner was sacked in July and Verstappen missed out on the drivers' title by two points.
Horner and Marko clashed numerous times during their time at the top of the team in a fractious relationship that was often characterized as a power struggle.
Marko rejected that assessment of their relationship in an interview with Dutch publication De Limburger, saying it was "nothing personal."
Marko also rejected the assertion that Horner's dismissal following the British Grand Prix was a victory for him personally.
"No," he said. "We had to act because performance on track was falling behind.
"And if we had done it earlier, we would have got things back on track sooner and Max Verstappen would have been world champion this year.
"I am absolutely convinced of that."
Marko claimed Horner moved to take control of the team following the death of Red Bull's co-owner Dietrich Mateschitz in 2022 by strengthening his relationship with Thai co-owner Chalerm Yoovidhya.
Marko said he worked within the team to counterbalance Horner's power on behalf of the Red Bull's headquarters in Austria.
"Together with Didi [Dietrich Mateschitz], I founded Red Bull Racing in 2005," Marko said. "We appointed Horner as team boss, and I was there as supervisor. Basically, the power was always in Austria, we decided.
"I remember a party in 2022 prior to the Austrian Grand Prix. Didi was there, but not in good health. Christian came to me then and said, 'He won't make it to the end of the year.'
"From that point on, he began cosying up to Chalerm Yoovidhya. When Didi died later that year, he did everything he could to take over with Yoovidhya's support. I did everything I could on behalf of 'Austria' to prevent that."
Marko went on to claim that Horner played "dirty tricks" in the final years of their time at the team.
Referencing comments he made about Sergio Perez to Servus TV following the 2023 Italian Grand Prix, in which he blamed Perez's fluctuating form on the Mexican driver's ethnicity and for which he later apologised, Marko appeared to claim the remarks were in some way "fabricated."
"But those final years with Horner were not pleasant," Marko added. "Dirty games were being played.
"Do you remember when it was claimed that I said Mexicans were less focused than Dutch or German people during Sergio Perez's time? That was fabricated -- possibly by them [Horner's camp].
"The same goes for the claim that in 2024 I spread the story that our engine development was behind schedule and that we would therefore lose Ford as a partner.
"I never said that, but Horner wanted to use it to have me suspended. Because of Max's support in Jeddah, that didn't happen."
When Red Bull announced Marko's departure last week it included a statement from the Austrian saying Verstappen missing out on the championship had moved him "deeply" and "made it clear" it was the right time to step down.
In his interview with De Limburger, Marko said he had not even read the Red Bull press release.
"I don't want to go into too much detail, but I didn't read that press release full of nonsense," he said.
"Let's just say that a lot has changed at the team in a short period of time. You think you know people well, but in the end that turns out not to be the case ... I really won't say more."
Marko said his decision to leave the team was made over the course of the final two races of the season.
"I hadn't been thinking about it myself for that long either. The idea of stopping started to take shape for me in Qatar," he said.
"I'm not much of a doubter; I'm quite decisive. On the Thursday before the final race in Abu Dhabi, I decided for myself that this would be my last weekend."