Carlos Sainz says it will take time to "adjust" to the Renault R.S.17 and to match the pace of new team-mate Nico Hülkenberg.
Sainz raced his final grand prix for Toro Rosso in Japan ahead of a move to Renault for the remainder of the 2017 season, as part of an early deal ahead of a full-time drive with the French manufacturer next year.
Having never driven the car, Sainz has warned that expectations must be kept in check and that matching his team-mate won't be an "automatic" thing – but rather something that will take a few races as he acclimatises.
"He has done 16 races with a car that I've never driven," said the Spaniard. "It will take me a while to adjust.
"Of course my goal is to reach his pace as soon as possible. But it's not automatic. You have to work hard for it. It is about analysing the data and learning how to drive that car."
Whilst there are drawbacks to an early switch, Sainz insists it will be beneficial in the long-term as it will prepare him better for 2018.
"I would not have minded finishing the season with Toro Rosso. But the early start can be very important," he added.
"It gives me an opportunity to get to know everything in the new team and to adapt the car to me.
"These four races will help me next year. And if I can get a few points for the team, that would be great."
