Ferrari had come in to the Singapore weekend braced for a tough time, with its SF-23 having appeared to struggle against the opposition at high-downforce tracks.
However, Sainz and team-mate Charles Leclerc were the surprises of the opening day of action as they headed both practice sessions around the Marina Bay circuit.
But while encouraged about the potential shown, and others suggesting the squad is now favourite for the race win, Sainz and Leclerc are still cautious because they know how much the form book can change over the weekend.
In particular, Sainz says that the way that falling track temperatures and a more rubbered-in track surface can make such a difference to the pace of cars through qualifying shows that Ferrari can take nothing for granted despite its early strength.
Read more: What we learned from Friday F1 practice at the 2023 Singapore Grand Prix
Asked after practice if he was surprised by Ferrari’s pace, Sainz said: “Yeah, a little. But at the same time, I think you always need to arrive to Singapore very open-minded.
“We've seen in the past very weird performance during Saturday's track [action], because it's a very particular track.
“But so far, it looks like it's suiting our car well, and it's going well with the way that we hit the ground running in FP1 and we could just fine tune the set-up a bit for FP2 and be a bit quicker.
“It looks good, but I do believe the track is going to change a lot. It's going to ramp up the grip a lot. And it's all about who finds the perfect set-up.”
Source: Autosport