Martin Whitmarsh has refused to comment on whether it is Lewis Hamilton's troubled private life that is steering his Formula One career on the wrong track.
Despite winning pole position and finishing a fighting second in Korea last weekend, the 2008 world champion was visibly and audibly despondent on the back of a terrible run of form and on and off-track incidents.
The Swiss newspaper Blick reports that his girlfriend Nicole Scherzinger has linked up with "a new man", pushing Hamilton in a foul mood that is affecting his job.
"The McLaren mechanics are upset with Lewis," reported veteran correspondent Roger Benoit, "because he treated them so coldly in Korea.
"They say he is behaving like a stubborn child."
Hamilton, 26, hinted at his split by saying he has received "massive support" from those close to him in the past days in the form of "emails from my brother, my mum and in particular my dad".
Any other enquiry regarding his state of happiness should be directed to Lewis
Team boss Whitmarsh also hinted at behind-the-scenes troubles by telling the PA Sport news agency that "professionally, he's happy".
"I comment on his professional life," said the McLaren principal.
"He says he is happy, and any other enquiry regarding his state of happiness should be directed to Lewis and not me."