Niki Lauda says any suggestion that Lewis Hamilton's Malaysian GP engine failure retirement was a result of Mercedes sabotage or favouritism is "ridiculous and stupid."
Hamilton had looked the odds-on favourite to comfortably win the Sepang race before his engine went up in smoke on lap 41.
The Briton's title defence prior to that had been marred by several other costly engine issues - and, after the latest setback, Hamilton's comment that "someone doesn't want me to win" was taken by some as a hint at intra-team sabotage.
Lauda, who serves as Mercedes' non-executive chairman, moved to assure that it couldn't have been Hamilton's intention to convey that message, and that any suggestion of sabotage is nonsensical.
"I know Lewis very well and he will not accuse the team," Lauda said. "This interpretation, I cannot accept it. Lewis knows we do everything possible to give him the best car and the best engine.
"I really feel sorry for him, I apologised to him that the engine failed. This was a young engine, not an old one, so we do not know the cause. So if we do not know the cause, nobody can say we sabotaged it.
"This is ridiculous. And if you speak to Lewis directly, I guess he will not say this.
"We worked for him and for Nico in a perfect way. He's won two championships so far with us, we've finished the most races ever. What do you guys think, we suddenly start to sabotage? Why? It's completely ridiculous and stupid."
Asked who Hamilton meant by his original comments, Lauda suggested Hamilton was referring to a higher power, the very interpretation that Hamilton himself has since confirmed.
On whether Mercedes had a preference in the outcome of the title battle between its two drivers, Lauda said: "We work for both cars the same way, we let them race the same way, all these questions are ridiculous."
Additional reporting by Jonathan Noble