Lewis Hamilton says he expects to have a "tough" time in his first season with Mercedes this year.
The 28-year-old has moved from McLaren and admits it is asking a lot to expect Mercedes to catch the top teams after a difficult 2012 season.
"It's going to be a tough season, without a doubt," Hamilton said.
He added: "You've got to be very understanding that (it) is going to be difficult for them in three months to gain two seconds or whatever it is."
Hamilton, who has signed a three-year contract, said Mercedes' attempts to catch top teams Red Bull, Ferrari and McLaren would be "a marathon not a sprint".
"It's the long haul," he added. "I hope this year we can be competitive. If we arrive at the first race and we are in front it's going to be spectacular but if we are not we just have to keep working at it.
"We might get to the first race and do outstandingly well but Red Bull, McLaren and Ferrari will also have been developing their cars. It's about building for the future."
The British driver said he expects to be able to deal with whatever competitive level the car was at without becoming downcast.
"You have got to remember that I had a couple of half dodgy cars (at McLaren), one particular year, 2009," he said. "But it did get better so perseverance is going to be key for all of us.
"I hope to have quite a big impact in those first days of driving the car (at the pre-season tests next month) because I'll be able to compare one car to the other and say what we do and don't have and what the car is and how it could be better.
"But it's going to take some time to get up to speed with the controls and the different settings, characteristics, aero balance. So I don't know how long it will take but I'm on top of it, I'm ready."
Hamilton was talking at a media call on his second day at the Mercedes factory in Northamptonshire.
It took place against the backdrop of BBC Sport's revelation that Mercedes plan to bring in McLaren technical director Paddy Lowe as part of a major restructure that could result in Ross Brawn being replaced as team principal.
Brawn won seven world titles with German Michael Schumacher at Benetton and Ferrari and the 2009 championships with his own team and Brit Jenson Button.
Brawn said on Thursday that he "planned" to stay on and "hoped" he was in Mercedes' plans. Hamilton said he knew nothing of the planned restructure.
"As far as I'm aware there are no plans to bring Paddy here," he said.
"I've been assured by Ross that his commitment is for the long term and he is here to try to win with me, which reassures me and continues to give me a positive feeling moving forward.
"There are lots of good people here and I've obviously had great experiences with Paddy but he works with McLaren as far as I'm concerned."
Asked how big a factor Brawn's presence was in his decision to join Mercedes, the 2008 world champion said: "There were tons of factors.
"I had to sit down and write down the pros and cons. That was on the list but it wasn't the deciding factor. There were lots of deciding factors.
"There is a great spirit here. The guys seem hungrier than any group of people I've seen before. They seem seriously hungry to win and excited they have another shot at it this year."
He dismissed a suggestion that the team was in "turmoil" and said he did not feel unsettled by the situation.
"It doesn't (distract me)," he said. "It's easy to be distracted, but I'm glad things are moving. They want to make changes because they want to win. I look at that as a positive not a negative."
Hamilton drove the 2013 car in the team's simulator on Wednesday and admitted Mercedes' device was not yet at the same level as McLaren's.
"We've got lots of work to do on it but it was great to drive, great to get a first impression of how the car was feeling," he said. "So I got to drive the 2013 car yesterday which was pretty good."