Ferrari's Fernando Alonso believes he can take points off title rival Sebastian Vettel of Red Bull despite qualifying eight places behind him.
Vettel qualified on pole with Alonso ninth
but the Spaniard will start eighth following a penalty for Lotus's Romain Grosjean.
Alonso said he had predicted the grid positions on Friday.
He added: "Everybody will think it's all over and we are sure we can score more points than Vettel.
"I don't know how but I have this feeling inside," he said.
Vettel can win the title if he scores 15 more points than Alonso
at the new Circuit of the Americas in Austin, Texas, on Sunday.
If the German wins, Alonso must be fourth or higher to take the championship to the final race of the season in Brazil next weekend. If Vettel is second, Alonso must be at least eighth and if he is third, Alonso must be 10th or better.
Lewis Hamilton qualified second ahead of Vettel's team-mate Mark Webber,
who was reprimanded by race stewards for missing a mandatory weight check. No penalty was handed out.
Alonso said: "I take maximum risk and maximum attack for seven months now, nothing [has] changed.
"In India [two races ago] we were very close with the McLarens on the exit of Turn Four. I think it will be the same [approach] tomorrow.
"We need to do a very good start; the places we made in the start and the first lap in the last three or four races were very important for our final result. Tomorrow we need to repeat that.
"It is going to be interesting to see how the race develops. [There's] strange behaviour of the tyres with very slow warm-up and very low degradation so it will be interesting to see what we can do in terms of strategy.
"Sunday is normally our best part of the weekend. We have always very good pace and we recover places all the time, and tomorrow I don't see any difference on that and I'm sure we will move up the positions.
"But I think overtaking will be tricky because the detection point of the DRS [overtaking aid] is just after the high-speed corner section in the first sector, so first lap will be the majority of the places we can gain. We need to plan this well."
Alonso said he had expected to struggle in qualifying.
"We were position seventh and ninth
in Abu Dhabi,"
he said. "The car is more or less the same. We are seventh and ninth in Austin, it is not surprising for us really."
He was out-qualified by team-mate Felipe Massa for only the second time this season.
But he said a mistake in running wide at Turn 19 on his penultimate lap when he was poised to set a faster lap time had not affected the result.
"In turn 19 yes it was off and then the tyres got a little bit dirty, so it was not good enough for the next three of four corners, but it was not this lap in Q3.
Alonso 'expected' qualifying struggle
"Felipe was quicker than me in FP3 [final practice], Q1, Q2 and Q3. He was doing a better job than me and tomorrow I will try to do a better job and recover some places."
Vettel said he would not be thinking about Alonso's position in the race.
"We know we are fighting for the championship," he said.
"We know the situation well, people like you are so kind and remind us all the time.
"It doesn't really matter where he is going to be in the race; we have to focus on ourselves and get the best possible result.
"If you go around thinking about where the other car is you don't do your optimum and we want to be the optimum because that enlarges your chances of doing well tomorrow and winning the championship this year.
"You don't have to be super-brain to know if you are ahead it is good and if you are behind its not so good."
United States Grand Prix 2012, day three
- Sunday, 18 November: Race 18:55 GMT; 5 live and live text commentary online. Race highlights; 22:25 GMT BBC One