The triple world champion told reporters that he will have to be the best he's ever been in the final three races to have a chance of taking a fourth title, and even then matters are out of his control.
But the Mercedes driver, who trails German team mate Nico Rosberg by 26 points, also emphasised that he was up for the toughest challenge.
"I don't feel like I arrive at a grand prix... and want it ever to be easy. I love doing things that are difficult," the Briton said.
"If I go rock climbing I don't go for the easiest wall to climb, I go to the hardest first. It is almost like your eyes are too big for your belly, you go for a bigger plate and you can't actually finish it.
"I always go for the hardest wall and sometimes make it, sometimes don't. I love the challenge. Would I like to be in a different position right now? Of course, but that is now where I am... I am ready to go. I am ready to fight."
Even if Hamilton wins the final three races, that may not be enough to retain the title.
Rosberg won in Mexico last year and needs only two second places and a third to emulate the achievement of his 1982 champion father Keke. He will take the crown in Mexico if he wins again and Hamilton finishes 10th or lower.
Hamilton said, however, that the odds made him feel slightly more relaxed. He would not be taking any extra risks but still racing flat out.
"I'm going for it, that's for sure. While my heart is still beating, I still have that drive to win, and there's still an opportunity. Even if it's only one per cent, I'm going to be going for it," said the champion.
"All I know is I've got to win and I'm going to try and do the best job I can in terms of getting the car (right), qualifying, driving. Really trying to apply everything I've learnt over all those years.
"If there's any time for me to be the best I've ever been, it's these last three races."
(Reporting by Alan Baldwin, editing by Simon Cambers)
