The Spaniard managed to put revisions to the SF-23 to good use at Barcelona as he emerged as Max Verstappen’s closest challenger for pole position.
But while the performance at such an aero-critical track bodes well for showing that Ferrari has found gains, Sainz believes that the nature of the Barcelona track has not actually played to its best potential.
He thinks that the high-speed nature of the venue does not especially suit the Ferrari, so clearer evidence of progress will come at future venues.
“The new package was meant to improve mainly the medium- to low-speed, and in that area, we have definitely felt a step in the right direction,” he said.
“As I said before the weekend, this is a step into a different direction. It is not so much a big upgrade or a big change in our performance, but it is opening a bit of a different window of working range for the car.
“That was the main target of this upgrade, not to suddenly go half a second quicker. I think that is doing the job and it's working well.
“We also want to make the car more predictable, more drivable, and easier to put together a lap. Hopefully it will go in this direction, but unfortunately we've come to a track that doesn't suit our package.
“Our high-speed performance really hasn't been good since the beginning of the season. Since Australia, we've been struggling with the balance and with the bouncing and still many things that are happening to us in high speed.
“So, we just want to now focus on that and see if we can improve that because, as you saw, low speed for us is actually not bad at all.”
Sainz believed that the fact he got Ferrari on the front row, while team-mate Charles Leclerc ended up getting knocked out in Q1, was further indication of one of his team’s biggest weaknesses – of it having a very narrow operating window where it is all too easy to suddenly be uncompetitive.
“I don't know exactly what happened to Charles, but it’s been the same story of the whole year,” he said.
“It feels like it’s a very narrow window for us; a very narrow window for the car; and a very tricky car to drive.
“As soon as the conditions get tricky, it can go one way or the other and you’re fighting very different balances. It's a very fine line for me today.
“It worked out okay, but it was tough because now it looks like the midfield is really starting to close-up with us. You have the likes of the Alpines, even the Haas, Lando [Norris] with the McLarens are appearing and just joining us in that fight for second or third best.
“Obviously Red Bull are in a league of their own but then everyone else, it looks like it's really, really tight out there.”
