Lewis Hamilton has conceded to feeling far from comfortable as the battle for this year's Formula One world title heads into the home straight.

Four successive victories for the second time this season have catapulted Hamilton into a 17-point lead over Mercedes team-mate Nico Rosberg.

The final three races of the season - in the United States this weekend, Brazil and Abu Dhabi - are crammed into the space of just four weekends, promising a frenetic denouement to a thoroughly dominant campaign for Mercedes.

Despite an appearance of calm, being within touching distance of his second world title is keeping the 29-year-old on edge.

Hamilton said: "It's a very positive feeling to have points and be finishing ahead of Nico but history has shown this year a gap can never be enough.

"The most important thing is the gap at the end of the year, so at the moment nothing changes."

He added: "There is never a comfortable feeling. I've never had a comfortable feeling in my life when I've been in a championship.

"It is tense all the way to the end, and this is a championship that is going to go to the end.

"We still have three races left to decide the drivers' championship, starting in Austin.

"I won the first ever grand prix at the track, so it's a special one for me. I really enjoy going there and I'm looking forward to another great race."