Despite topping Friday's second practice session in Mexico City, Ferrari's Sebastian Vettel remains cautious on his prospects, insisting that only small performance margins separate the top three teams.
Vettel emerged as the fastest runner in the afternoon session despite undertaking limited single-lap running on Pirelli's soft compound as he focused mainly on race simulation on the medium tyre.
The four-time world champion enjoyed a small one tenth edge over Red Bull's Max Verstappen and almost a half a second advantage over teammate Charles Leclerc.
Still, Vettel refused to put the cart before the prancing horse ahead of qualifying.
"Charles and I split the work today," Vettel said.
"I did most of the work on the medium tyre, which was ok. We don’t look that bad, but I don’t have the full picture yet.
"I did only two laps on new Softs so it’s difficult to say, but I don’t think I had the worst tyre today for the long runs.
"However there are still some areas where we can improve tomorrow in terms of the general balance and the feeling I have with the car.
"Max looks strong, but all the three top teams are very close, so let’s see what tomorrow brings."
Leclerc's day almost ended in drama when the Monegasque suffered a spin at the very end of FP2 and narrowly avoided a contact with the barriers.
The 22-year-old's work on the soft tyre looked tricky from the outside as the SF90 appeared to struggle for grip, an impression later confirmed by the Ferrari charger.
"I struggled a bit with the car balance and there are still some improvements I want to make in my driving," explained Leclerc.
"In general, the grip is rather poor on this track because we find ourselves at such a high altitude and the downforce is not as efficient as it is at other tracks."
Leclerc sees this afternoon's qualifying as crucial as position on the grid and a good launch off the line are paramount.
"To win this race, you have to get a good start and keep the lead well into Turn 1," he added.
"Being behind someone is a disadvantage here because of the cooling issues everyone faces, so having a strong qualifying result will be a key factor.
"Our competitors are strong and we will see where we really stand tomorrow, but we are confident of our potential and ready to give it our all once again."
If Ferrari locks out the front row, will the Scuderia resort to team tactics to fend off its rivals like in Japan?
"We haven’t discussed a plan," said Leclerc. "We’ll be doing what the team asks, so if they ask us to do so it will be done."
Hopefully with a better outcome for Leclerc than at Suzuka...