Lewis Hamilton says he is convinced Ferrari have designated Sebastian Vettel as their number one driver.
Vettel won the Monaco Grand Prix after Ferrari's pit-stop strategy helped him beat team-mate Kimi Raikkonen.
Hamilton said: "It's very clear Ferrari have chosen their number one driver and are pushing everything to make sure Sebastian will maximise his points.
"It is very hard for the leading car to get jumped unless the team decide to favour the other car."
But Hamilton said he would not be asking Mercedes to favour him in the same way over team-mate Valtteri Bottas.
"I haven't spoken to the team and I don't really plan to," Hamilton said. "Valtteri has been doing a great job and I don't currently feel we have to favour one or the other.
"It is really important we collectively work as a team more than ever before, as we have been, because our work is to beat the Ferraris in the constructors' but there might be some things along the way positioning-wise that might become valuable.
"Who knows what will happen? It might be the other way. We might need to give him the upper hand. We just need to make sure we are ahead of them so we are not in the same scenario as we are today."
Hamilton finished seventh in Monaco after starting 13th following a messy qualifying session in which he made a series of mistakes.
Mercedes' weekend was blighted by problems making the ultra-soft tyre work at its best consistently, a problem that also afflicted Hamilton two races ago in Russia.
Hamilton said: "Common sense is of course I cannot afford another weekend like this at the going rate when the Ferraris are quick; of course not.
"Just because I can't afford for something doesn't mean it's not going to happen. There is no point worrying about it. You just work towards trying to rectify whatever issues you have and hope you don't have them again. Things just didn't come right to us, the car was in a difficult place.
"The Ferrari seems to work everywhere so these next 14 races are going to be very difficult.
"This car is not working everywhere we go but the more races we do the more we learn and the stronger we get. Ferraris are not bullet-proof they have things coming up potentially with all the turbos they have used, so we will see."