Lewis Hamilton admitted his difficult start to life at Ferrari could last all season.
Hamilton moved to Ferrari after 12 years with Mercedes in a transfer billed as the biggest in Formula One history.
Although Hamilton won a sprint race at the second round in China, he has failed to finish inside the top four in a main event.
The 40-year-old has also been out-qualified by team-mate Charles Leclerc at all but one of the opening five races, and has finished behind the Monegasque in every grand prix.
Speaking ahead of this weekend’s round in Miami, Hamilton said: “When I joined Mercedes in 2012, the first six months were tough, getting in tune with all the new people.
“The engineers I work with now are used to setting up the car for a different driver, and a different driving style and I am used to driving a car with a different driving style. So there are a combination of lots of things.
“I am working hard to adjust to this car, that’s for sure. And I have no clue what to expect in Miami. We will do the best we can.”
Quizzed on whether he expected his “tough” six months at Mercedes to be replicated with Ferrari, Hamilton conceded: “I really don’t know. I genuinely don’t.
“We are working as hard as we can to shorten that, but it could be longer, who knows?”
Hamilton moved to Ferrari to land a record eighth world championship, but his beginnings have courted criticism.
Earlier this week, former driver Ralf Schumacher, brother of seven-time world champion Michael Schumacher, claimed Hamilton may even retire before his two-year contract with Ferrari expires.
Hamilton said: “I just don’t think about it (the criticism) and not to focus on opinions of people who have no insight as to what is actually going on and insight from individuals that have never been in my position. I will just keep my head down.”
