Nico Rosberg has said that he was not to blame for a technical issue that contributed to the crash with Lewis Hamilton last Sunday.
After Mercedes's team chairman pointed the clear finger of blame at Hamilton, boss Toto Wolff explained that it was German Rosberg who was in "the wrong engine setting".
"That was the reason he was significantly slower than Lewis," he said. "This explains why everything happened so quickly."
The implication is that Rosberg simply made a technical mistake under the new anti-radio communication regime, but the championship leader denies that.
"Suddenly I lacked power," Rosberg told Bild on Tuesday after testing in Barcelona.
"The switch for the engine mode was not in the correct position so we need to investigate why that was so."
Rosberg said that he even attempted to correct the situation mid-corner "but nothing happened".
As for whether he or Hamilton should take any of the blame, the German did not want to talk about it.
"It felt good to be back in the car [for testing] but Barcelona is finished now and I'm only thinking of Monaco.
"We go there with confidence but also keeping our minds on Red Bull and Ferrari."
Concerning Mercedes's chances in Monaco, he answered: "I'm confident that we will be very competitive there. Clearly I want to get my fourth win in a row."
Rosberg leads the drivers' championship by 39 points to Ferrari's Kimi Raikkonen.