The SF-23 has been quick over one lap in qualifying thus far this season but has usually lost out to Mercedes, and often Aston Martin, over a race distance.
That pattern was repeated in the Spanish GP when Carlos Sainz qualified second but was jumped by both Mercedes drivers, as well as the Red Bull of Sergio Perez, in the race.
Vasseur indicated that the ongoing strong qualifying form demonstrated that the latest upgrade package had worked well.
"We made a step forward in terms of potential,” he said. “The reference in Miami. In quali pace at least we were able to put Carlos on the first row, a step forward probably.
“On the race you could consider that we made a step forward compared to Aston, but it's far from enough.
“We still have a huge delta in terms of performance with Mercedes, quali to race. It's where we have to put all the focus of the company and if we want to come back and to have good races on Sunday so that we are scoring points."
Vasseur believes that Ferrari will be able to challenge Mercedes in races once it has solved its issues: “I think as soon as we unlock the situation with consistency we can imagine fighting with them all over the race.
“With Red Bull, it's another story, especially with [Max] Verstappen. He is still much faster than us in quali, much faster in the race.”
Source: Autosport