Sebastian Vettel had a mixed reaction despite setting the quickest time in Friday practice at the Brazilian Grand Prix.

The German led a Scuderia 1-2 in the afternoon at Interlagos after morning rain had restricted the amount of meaningful running.

While broadly happy with the performance of his SF90 though, Vettel did acknowledge some optimisations remained.

“There are a lot of small things and we need to make sure we nail those,” he said via Crash.net.

“The car was decent today but we can improve. I’m confident of a step forward."

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“In the race it will be difficult because others are quite a bit faster than us," the four-time champion suggested. "But that’s pretty much in line with the picture we’ve seen in the last couple of races so I’m not surprised.

“I think we can work on ourselves and be in a better shape for tomorrow. We do our homework from now and see where it takes us.”

Also notable on Friday was, after weeks of FIA directives and questions over Ferrari's engine, Mercedes and Red Bull revealed a disadvantage of around 0.7s on the straight, hinting their Austin speed was only a one-off.

“It’s a bit sad that generally opinion swings so quickly nowadays and it doesn’t take much, it takes one and a half hours and everything is completely different and it takes one race only to make that up,” Vettel said responding to the reaction.

“I think the main thing for us is to focus on ourselves and hopefully give the right answer on the track.”

As for teammate Charles Leclerc, a strong qualifying will minimise the damage from his 10-place grid drop for a new engine and he was content with how his Friday went.

“It was a positive day in general, even though the conditions were quite tricky," he commented.

“It's the same for everyone, and I think we were quite competitive, so that's good, and now we look forward to tomorrow.

“We will need to anticipate the track evolution and the setup of the car to try and be as strong as possible on Sunday when it matters.”