Last year tyre management over race stints was a major weakness for Ferrari, with a lack of consistency across stints and from set to set.
The SF-24 has been competitive over long runs at the first four events of the season, with Carlos Sainz winning in Australia and the team making the podium in the other three races.
However, Vasseur still wants to see how the car performs at other venues and in cooler conditions after hot weather dominated the early events of the season.
“I think from the beginning of the season we are much better on the tyre management,” he said after the Suzuka race.
“And degradation – I think we were able to do the fastest lap in Jeddah and Melbourne on the last lap. It was almost the case today for one-tenth, I think.
“We did a very good step forward on this one, we worked a lot on the weaknesses, and we improved massively on the tyre management, drivers, strategy, and the team.
“And yeah, now we have some other weaknesses, and we have to improve somewhere else if we want to do a better job.
“But I think this one is very well under control now. But what is true one day, it's not true the other day, on the tyre management and we don't have to consider that this is done.
“Next week in China will have another tarmac, different weather conditions, and it will be a new challenge.
Asked if cooler conditions might help Ferrari in its chase of Red Bull Vasseur said: "In China, we will have the opportunity to test in colder conditions. But I don't know, because also we did only FP3 [in Japan] in colder conditions.
“I'm not sure that we are in a better shape, you never know about the engine settings, level of fuel. The deg was under control for us on Saturday, but also for them. And it was almost the same today.”
Vasseur noted that the outcome of the Suzuka race, which saw Sainz and team-mate Charles Leclerc finish third and fourth, was as good as it could have been.
“I think that everything went very well on Sunday,” he said. “The strategy was the good one for both cars, the defending of the position on track, tyre management was under control, the pitstops went well, the pace was okay.
“I'm very convinced that we need a good Sunday and if we have to change something, it's more the Saturday that we have to improve, rather than the Sunday. But it was a good job, and a good teamwork.”
Watch: F1 2024 Japanese Grand Prix Review – Normal Service Resumed
