The triple world champion comfortably topped the morning session, edging Rosberg by over half a second.
But the German responded in the afternoon by going 0.4s faster than his rival in FP2.
Still looking for that elusive first win at Interlagos, the Briton feels it will be neck-and-neck with Rosberg, who had secured victory at Autodromo José Carlos Pace 12 months ago.
“I think it’s going to be close, that’s for sure,” he commented afterwards. “Nico’s driving really well so it’s going to be close.”
Hamilton also has an explanation as to why he went from being five tenths up to nearly 0.5s down in the span of only a few hours.
“The set-up changes take quite a long time and I was kind of stuck with a choice that I’d made from FP1 that probably wasn’t the right one but we’ll make it for FP3 and it should be good.
“I didn’t change anything in the car for the second free practice so in terms of the evolution in the track I didn’t follow that. Maybe that’s a disadvantage but I will make some changes tonight, for sure.”
Last year’s Brazilian Grand Prix had seen drivers set faster lap times on Friday. While a few spots of rain came down in FP2, Hamilton believes the drop in pace has more to do with a couple of changes in the track layout.
“I’m pretty certain it’s just the kerbs. Turn 2 is a big, big kerb, it used to be flat through there but now you have a lift. Turn 8 has a big kerb now, we used to just run over the whole of it and now you can’t. Those two corners on their own make a big difference.”
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