The Spaniard and his team-mate Charles Leclerc have struggled for much of this season with their SF-23 proving to have a lack of consistency, especially on Sundays.
This has left the duo unable to take the fight to Red Bull in grands prix, even though in qualifying the car has often shown itself to be quite close to the RB19.
Ferrari has seen signs of progress in recent weeks with its understanding of what it needs to do, but it is still not yet at a stage where it feels confident it has addressed all the factors at play.
Reflecting on why Ferrari faced the unexpected difficulties, Sainz thinks that there was already evidence last year about there being a race-pace question mark over its F1 challenger.
“If you analyse it a bit as a bigger picture, already towards the second half of last year you could see that we had a car capable of fighting for pole positions but, in the race, we were always getting beaten by Red Bull,” Sainz told Autosport in an exclusive interview.
“People a lot of times were blaming it on the strategy. But actually, I think a lot of times we were just never as fast as them in the race, like in Budapest or in Austin, or places where we put it on pole and then we went backwards.
“Maybe the difference there was that we were on pole by one-tenth, and then on race pace, we were down by two or three-tenths.
“But the delta itself this year is we are half a second off in some qualifying, and then eight-tenths in the race. So, it's some bigger deltas maybe.”
Source: Autosport