PARIS (AP) — The Mercedes Formula One team published an open letter to fans on Wednesday to counter speculation on social media following the Russian Grand Prix that it favors Nico Rosberg over teammate Lewis Hamilton.
Hamilton, the defending F1 champion, has endured a miserable start to the season and trails Rosberg by 43 points after four races - all of them won by Rosberg, last year's runner-up.
While Rosberg has driven smoothly as he chases his first world title, Hamilton has been beset by engine problems and the British driver also had to slow down late in Sunday's Russian GP with a water pressure issue - just as he was closing to within seven seconds of race-leader Rosberg.
Without responding directly to allegations of favoritism, Mercedes still took the trouble to underline that team staff members are not working more ''for one driver or the other - but for each other'' and that ''there is no `A' or `B' team here.''
Mercedes then concluded its letter with a defiant tone to any who suggest wrongdoing.
''To those who stand with us, we thank you. And to the rest - the haters, the naysayers, the conspirators -if we can convince even half of you of what we really stand for, we'll consider that a battle well won,'' Mercedes said.
At the Sochi circuit last weekend, Rosberg took pole position while Hamilton started from 10th place on the grid after another engine failure - caused by an overheating component in the car's energy recovery system - curtailed his qualifying session early on Saturday.
Rosberg eased to his seventh straight victory after winning the last three races of the previous season, taking a firm grip on this year's championship.
Meanwhile, a frustrated Hamilton said he was ''very, very curious'' about what went wrong and has asked for ''as much detail as possible'' from the team.
In China, the race before, Rosberg again took pole while Hamilton started from the back of the grid because of a similar engine failure. Hamilton was only able to take part in the Russian GP after his team flew out emergency machine parts and worked on his car through the night.
Mercedes said in Wednesday's letter that it remains ''baffled and gutted'' by Hamilton's ongoing engine problems.
''Our goal is not simply to be fast but bulletproof, too,'' Mercedes said. ''Not just to manage the problems but to understand them, fix them and ensure they are not repeated.''
But these ongoing engine issues mean that Hamilton, who is seeking a fourth world title, could face further grid penalties during the season if he uses more than the allocated numbers of engines and engine spare parts.
Hamilton, who finished seventh at the Chinese GP despite starting last, placed second in Russia after another strong drive through the field and despite a late problem with his car's water pressure.
''The job he did to nurse the car home and still retain second place was truly remarkable,'' Mercedes said Wednesday.
Last year, Mercedes was untouchable as both drivers had a near glitch-free season, with Hamilton wrapping up the title with three races to spare.
Both pre-season testing runs in Spain suggested that Mercedes would be as reliable as ever this year, making Hamilton's problems now all the more unusual.
''This is a mechanical sport, balancing on the knife-edge of performance and endurance,'' Mercedes said. ''You have to push the boundaries and failures can happen.''