The new SF-24 has looked good from the start of testing in Bahrain, and crucially its on-track behaviour has mirrored that seen in the Maranello simulator.
Team-mate Carlos Sainz led the second day of testing outright, while Leclerc was fastest in the truncated morning running.
Leclerc says that the team is in a much better position than it was 12 months ago, and it has a good base on which to build as it develops the car.
"We're making good progress," he said. "Once again the car is doing what it needs to do, which wasn't the case at the start of last year.
"I remember after the first few days, I was much more worried because it was a very, very complicated car to drive. This year it's easier, so it's starting from a better base, but there's still a lot of work to do.
"For the time being, everything's going according to plan, in the sense that we haven't had any unpleasant surprises in terms of the car's behaviour."
Leclerc says the fact that the car has reacted as the simulator had predicted will help to accelerate development.
"The car is behaving as it did in the simulator, so that's a pretty good sign," he said. "After that, in terms of competitiveness, it's too early to say.
Source: Autosport