On a day of soaring heat and rising tension, the 27-year-old Briton clocked a best lap time in one minute and 14.026 seconds to outpace defending champion German Sebastian Vettel of Red Bull.
Vettel, who leads the title race by 13 points ahead of Sunday’s finale, only needs to finish in the top four to become the youngest triple world champion in Formula One history.
His only rival for the title, two-time champion Fernando Alonso of Ferrari, was fifth fastest, separated from the front pair by Vettel’s Red Bull team-mate Australian Mark Webber and his own in-form Ferrari team-mate and local hero Felipe Massa.
Vettel was three-tenths of a second slower than Hamilton while Webber, Massa and Alonso were so closely matched that they were separated by just 0.007 seconds at the end of the afternoon session.
The defending champion was mindful of the forecasts for unpredictable weather with heavy rainstorms on Saturday night and Sunday.
“It was very slippery for everyone, quite hot today and in terms of track conditions not that easy. So everyone suffered the same kind of problems – track, stability and so on — so we have to do our homework now no matter what the weather forecast says,” said the German.
Asked if he felt confident he could clinch his third title, he said: “We will see. It is a bit unknown what is going to come. So far we can be happy. We have to do our homework and improve the car, there is a lot still to come.
“Obviously we don’t know what the weather is going to do. Today is incredibly hot, tomorrow is supposed to be hot with maybe some rain, and Sunday a bit cooler — this is Sao Paulo so it could be anything.”
Hamilton, who won the United States Grand Prix in Austin last weekend, and won the 2008 title in dramatic fashion at Interlagos, topped the times in both sessions and looked supremely confident and fast in his 110th and final race for McLaren before his impending move to Mercedes next season.
He showed his emotion by reportedly bursting into tears during a television interview on Thursday and by adding the slogan ‘Thank You McLaren’ to his bright yellow helmet.
“It’s been a positive first day — I hope we can maintain our form or even progress it tomorrow. We’re certainly looking strong, but this place can be so tough on tyres that it’s hard to make any accurate predictions at this stage,” said Hamilton.
“The track and ambient temperatures were so high today that it felt almost as though I was sliding around the track with the tyres melting.”
“It’s great to have such a positive final Friday with the team — it’s been one of the best Fridays we’ve had for a long, long time. I’m savouring every moment of this weekend.”
Seven-time champion Michael Schumacher was sixth fastest for Mercedes, in his final Friday practice session before heading off into retirement at the age of 43 and with tributes ringing in his ears.
His Mercedes team-mate and fellow-German Nico Rosberg was seventh ahead of Hamilton’s McLaren team-mate and compatriot Jenson Button, Frenchman Romain Grosjean of Lotus and Briton Paul Di Resta of Force India.
After a warm, bright morning, the afternoon session was run in hot, dry early summer weather with the air temperature rising to 33 degrees and the track temperature into the mid-40s, conditions that meant tyres had to be treated with great respect.
The track peaked at 49 degrees.
But a weather forecast of heavy rain due to arrive late on Saturday and into the weekend, posed questions for the teams’ set-ups with some opting for more down-force than others.
Alonso and Ferrari were among the teams that seemed to favour higher levels of downforce, which would be an advantage in wet conditions, and after the early fast laps from Vettel, he jumped top of the times midway through the session.
Grosjean then replaced him as fastest man before he was, in turn, outpaced by Hamilton’s crushing lap in one minute and 14.026 seconds with 37 minutes remaining as they switched to softer medium compound tyres.
Massa and Rosberg also lapped more quickly and clocked the second and third-fastest times before Vettel, on fresh tyres, went on a charge but was still 0.274 seconds slower than Hamilton who concluded his work with an impressive long run in the final minutes.