The new SF-24 has looked good from the start of track running in Bahrain, and crucially its on-track behaviour has mirrored that seen in the Maranello simulator.
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.
"In itself, the fact that it behaves exactly as it did in the simulator is good news. It allows us to be able to develop the car in the virtual world at Maranello, and that's good."
Expanding on the improvement compared to 12 months ago, he said: "In terms of driveability, the car is a lot better compared to last year. Last year after the test, it was very, very difficult to push into a direction, because we just didn't know what the car was doing.
"We would get into a corner and we didn't know whether we will have extreme oversteer or extreme understeer. Which was a big problem. This year, the car is not like that, which is a better starting point."
However, Leclerc cautioned that it's too early to get a clear picture of the overall 2024 pecking order.
"It feels like every winter test, which means that we don't understand a thing," he said. "Because for now, it's too early to say, we have no idea what are the fuel levels of everybody else.
"My initial feeling is that Red Bull unfortunately remains quite a bit ahead. They have done very impressive lap times.
"But this is only my own feeling, not looking at data, because again data doesn't mean much for now."
