Hamilton was two tenths off Sebastian Vettel's headline time by the end of Friday at Interlagos, although the German's lap was compromised by Valtteri Bottas.
The Finn also got in Hamilton's way as qualifying sims ramped up in Brazil.
And while Hamilton says there remains plenty of time on the track for the Silver Arrows, he expects the Scuderia will also make gains, although Ferrari's efforts will be hampered across the weekend by Charles Leclerc's impending 10-place grid penalty.
Hamilton said: "It started out really well so straightaway from the get go we started on a good baseline and we just made a couple adjustments in that short space of time we had in the session and then we'll do some work tonight to refine it.
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