Autosport, RaceFans and BBC Sport have reported:

Mercedes team principal Toto Wolff has rejected claims that the team is favouring Kimi Antonelli over George Russell, calling the accusations “brainless” and “completely nonsensical.” The dispute has intensified after Russell’s engine failure in Malaysia led to another power unit replacement and a grid penalty for this weekend’s Singapore Grand Prix, while Antonelli is running Mercedes’ latest car specification and Russell has reverted to the older one.

Russell will start the Singapore race from the back of the grid after Mercedes replaced his power unit following his retirement in Malaysia. The British driver’s championship hopes were described as all but extinguished after the failure, which came while he was running third. Reports differ on his deficit to Antonelli: one put it at 84 points and another at 86, with the latter describing Russell as entering the Singapore weekend 86 points behind his team-mate.

The engine failure forced Russell into an early power unit change and a penalty, after Mercedes had expected he might benefit from the ADUO upgrade later in the month. Russell himself had suggested reverting to the previous car specification could be worthwhile. He won in Baku with that version before the team introduced revised floor and sidepods at Sepang, where Red Bull secured its first win of the season.

Mercedes is splitting the car specifications at Marina Bay after the upgrade introduced in Malaysia failed to deliver the expected performance step. Antonelli is using the newer parts, while Russell is on the older aerodynamic package. The decision has fuelled online theories that Mercedes is giving Antonelli an advantage. Wolff’s impassive expression during a brief screen appearance as Russell retired in Malaysia also added to the speculation.

Asked about the claims at a Friday press conference in Singapore, Wolff said: “They’re brainless, whoever thinks that. I mean, it’s completely nonsensical. We’ve had it in the past with Lewis [Hamilton] fans. I mean, literally, I don’t know what’s going on. Do they think I have a button that says, ‘George engine failure now’, or disadvantaging one driver against the other when we are fighting for a constructors’ championship, when we have always had the mindset of providing everybody equal material?”

Wolff said he had little respect for people making the accusations and dismissed the way some critics post online. “Really [I have] zero understanding and respect for people who come up with these things,” he said. “Rather than watching Formula 1, they should do Teletubbies or some Mickey Mouse.” In another version of the remark, he said those critics should watch “Teletubbies” or “some Mickey Mouses.”

He added: “I guess this is maybe where social media goes today. People hide behind their screens and then they lash out. There’s a lot of polarisation going on, and sometimes I read what people write, I find it hilarious. These people really contribute to my own entertainment when they are abusing the team or myself. I’m Satan, I’ve heard. So, yeah, overall it’s funny.”

Wolff said neither driver believes Mercedes is favouring one over the other and described a policy of balanced and transparent treatment that he has pursued since joining the team’s leadership in 2013. He recalled meeting Alain Prost as a rookie and asking why things had gone wrong between Prost and Ayrton Senna. “Because we never knew what the team was about,” Wolff recalled Prost saying, describing how drivers could feel wanted at one point and then believe team politics had turned against them.

“I took it as my challenge to keep it always balanced,” Wolff said. He added that it had not been easy during the period when Lewis Hamilton and Nico Rosberg were team-mates. “That’s why people can think what they want, but the integrity in that respect is something that’s important for me, and the drivers know it.”

Wolff highlighted the long connections both drivers have with Mercedes. “We have had Kimi since he was 11,” he said, calling Antonelli an integral part of the team and praising the young driver’s talent as he fights for a championship. Russell has been associated with Mercedes since he was 17, Wolff said. He described feeling strong emotions and compassion for Russell, adding that they are close.

Wolff said he and his wife, Susie, spend time away from the track with Russell and his fiancée, Carmen Montero Mundt. “We are spending time with Carmen and Susie off the track with each other,” he said, noting that they travel together, visit the same coffee shop and go to the gym. He called the accusations annoying and said he pays no attention to them. “Most important is that George knows how the team is and Kimi knows, and we will always try to give them equal opportunity.”

Wolff said Mercedes does not yet know which specification will be quicker. “When it comes to the upgrade, it’s a good example,” he said. “We don’t know which one is going to be quicker. So you take a decision and say, ‘Let’s try to find out.’ And there is no great political thinking behind it.” He said the team does not want its drivers to block one another, and that the quicker car behind has an advantage regardless of which driver is in it.

He said early indications suggested the new car was more difficult to drive, but not necessarily slower, and that Mercedes might not yet have found the right set-up. The older car felt more stable and grippy, he said, while cautioning that this was based on one free practice session and more time would be needed for conclusive information. The upgrade is Mercedes’ first significant design change since June.

Wolff said the results could affect the team’s preparations for 2027 after months of development in a direction Mercedes believes will be advantageous. “Even if it is now that it’s more realistic for Kimi to win a championship in sheer mathematical probability, we would still give George the same opportunities,” he said. “That’s the ethos and the integrity on which the team has operated since 2013, since I came, and we are going to stick to that. And then people can think what they want.”

Russell was quickest in the old-spec Mercedes during Singapore practice, while Antonelli and the two Red Bull drivers saved tyres. Other updates around the weekend included Russell acknowledging his performances had not been good enough this year regardless of luck, Lando Norris saying a fuel system problem had “cost me quite a lot” in recent races, and Esteban Ocon ruling out racing elsewhere in 2027. Williams driver Carlos Sainz said his team had “completely missed this set of regulations and got it really wrong.” The Singapore weekend also marked the fourth time this season an F1 heat hazard had been declared.