Sainz currently has a 10-place grid penalty for taking a new control electronics on Friday, and he is expected to be consigned to the back of the grid after taking further new power unit elements before Saturday’s FP1 session.
Ferrari has opted to take the hit in France because it’s so difficult to overtake at the next race in Hungary, but on Friday Sainz discovered that it might not be so easy at Paul Ricard either.
The Spaniard says that finding extra straightline speed would be the “best medicine” to help him gain positions.
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"I tried a couple of moments with other cars to overtake, because I know I'm going to need to overtake a lot,” he said.
“And I must say that it was a bit trickier than expected mainly because there's a tailwind on the back straight and, with this tailwind, it looks like the slipstream and DRS effect is a bit low.
“But I don't have any other choice, I need to find ways to overtake and the best medicine for that is to just be a bit quicker come Sunday than what we are.
“Let's see when everyone is running the engines modes flat out if we have the top speed to overtake. I hope we do, because I need to make up a lot of places."
Asked to confirm that he will indeed be sent to the back, Sainz said: “We will see... I mean I took 10, so you can expect what's coming next."
Sainz, who was fastest overall on Friday, was encouraged by the general form of the car.
"Well, it was definitely a positive Friday, at the end not many laps on the short run on the low fuel, but every lap that I did was competitive," he said.
“So it shows that the steps that we're taking and the direction that we're taking is going in the right direction, focusing more in the long run because I'm not going to be in that fight for pole position, given the amount of penalties, and in the long run there's a bit of work to do but, at the same time, some encouragement from the short run."
He also indicated that tyre degradation will be a major factor in the hot conditions: "It is very hot and, so far this year, every time we've seen it's been hot the deg increases massively on these new Pirelli 18-inch tyres, and it's going to be higher deg I think than what it's been in the past here in Paul Ricard.
“So there's work to do. Max [Verstappen] was very quick on the medium tyre, I was quick at the beginning and slow at the end, so all that speed that I had in the short run, I wanted to make sure that it translates into the long run."
Sainz’s team-mate Charles Leclerc was also positive about the car, but admitted that the team wasn’t sure about the true potential of main rival Red Bull.
"We still have to work on the car a little bit for tomorrow,” he said. “It's very difficult to understand, because it felt like Red Bull is doing something different to us on Friday.
"But, focusing on ourselves, the feeling is good. So yeah, we just need to put everything together, and the pace is in the car.
"Max seems to be particularly quick today on the high fuel, so I don't know how much fuel they were running. That is a bit the question mark. But yeah, let's see tomorrow.
"Again the pace is in the car, we just need to focus on ourselves, and if we do the perfect weekend, we'll be fighting for the win."