Hamilton holds a 66-point lead over Ferrari's Sebastian Vettel heading into the race at Autodromo Hermanos Rodríguez.
Lewis Hamilton targets 'a couple more years' in F1 as Mercedes driver closes in on fourth world title at Mexican Grand Prix
Lewis Hamilton has said he can "easily imagine" life without Formula One but insisted any talk of immediate retirement were wide of the mark as he closes in on a fourth world title.
Hamilton, 32, hailed one of his "best drives" on Friday despite being outpaced by Daniel Ricciardo during second free practice for this weekend's Mexican Grand Prix, where on Sunday he hopes to seal the title.
Earlier, he had suggested that a fourth world title would not usher him towards retirement and hinted that he is likely to remain in the sport for the next few years.
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"I can easily imagine myself without Formula One, but it is not about that right now," he said. "There are some really cool things coming along that are going to complement where I am in Formula One."
He declined to elaborate on his plans, but conceded that he had been in Los Angeles earlier in the week to discuss "creations" he was working on.
"I definitely won't be here at 40," he said. "I don't think that is going to happen, but it changes all the time. There have been times when I thought I am happy to move on, but you can't come back.
"I can't tell you how long I will be here for, but eventually I will figure it out and know when the time comes. I anticipate a couple more years at least."
Hamilton said also that winning a fourth title would not elevate him beyond his childhood hero, Brazilian Ayrton Senna, who won three championships before his death in the 1994 San Marino Grand Prix.
"Ayrton's life was cut short and I think, had he the opportunity to continue and race in safe conditions, he would have continued to win more championships," Hamilton said.
"I don't look upon him and think that I am better because I have more wins and championships and poles, but I feel very proud for my name to be mentioned alongside his name, and that's all."
Looking back on his early years in F1 with McLaren and his first championship win, he said: "In 2008 I was a kid. I had all the natural talent I have today, but I didn't have the knowledge or experience.
"I'm much better equipped now than I was in 2008. It's actually been more enjoyable this year being in the position I am. I'm a lot more comfortable in my own skin so that's really helped me.
"I'm now fighting a championship-winning team in Ferrari and a champion driver, but I'm much better equipped. It's actually been more enjoyable this year being in the position I am.
"When you are 18, you think you know everything, but you don't know anything."
On Friday, Hamilton wound up second in both sessions, having also been outpaced by Mercedes teammate Valtteri Bottas in the morning.
"It's been a good day," Hamilton said. "It didn't really start out great, particularly in the second session with the big spin on my first lap that really threw me off the session and made it a little bit tricky to get the run on the super-soft tyres.
"I had put myself on the back foot, but the single lap and then the long run on the ultra-soft was probably one of the best I've ever done.
"I don't think I've ever done 26 laps that consistent, apart from in a race maybe.
"We got lots of information, the track was feeling better in the second session once the temperature came up -- so, overall, it was a good day."