Lewis Hamilton doubts he will be able to claim the Formula One world championship at the United States Grand Prix unless rival Sebastian Vettel makes a "silly mistake" in Austin.

Championship leader Hamilton is closing in on a fourth F1 title after taking pole position ahead of Ferrari's Vettel on Saturday.

Hamilton – who has taken 118 points from a possible 125 across the last five races – qualified fastest with a time of 1:33:108, two tenths faster than Vettel as the German lines up on the front row for Sunday's showdown.

But Hamilton knows he will need some luck to wrap up the championship this weekend, with Vettel having to finish lower than fifth to pave the way for the Mercedes star to reign supreme.

"It's highly unlikely it's going to be the case, Sebastian did a great job to bring the Ferrari back up," Hamilton said. "I think ultimately all I can do is do the best I can with my abilities and try to get maximum points.

"Sebastian is right there so, unless he makes a silly mistake which is unlikely it will go to the next races. It's going to be a great race out here tomorrow [Sunday], going be a tough one because looking after the tyres in these conditions is still tough but looking forward to it.

"The track was very difficult today, with the wind picking up you've got a headwind into turn one, a tailwind out of turn one, whole of sector one is tailwind and then a headwind into turn nine, so it's shifting the whole way through the lap.

"You're kind of gauging how hard you can push, how much must lay off. But that's why I love it here, such a fantastic track to drive and especially when you've got a car you can rely on."