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 going into the final three grands prix of the year.

The trio of races 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.

Yet despite the 29-year-old appearing appearing calm, deep inside the prospect of being within touching distance of his second world title is keeping Hamilton on edge.

Asked whether he felt in control for the first time this season, as for the majority of the year he has been hunter rather than hunted, Hamilton replied: "No, I don't.

"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 is at the end of the year, so at the moment nothing changes."

As for any comfort with regard to his position, and the largest cushion he has held over Rosberg, Hamilton 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's tense all the way to the end, and this is a championship that is going to go to the end.

"I just hope the future is bright for the next three races."

With nine wins to his name this season - only Michael Schumacher and Sebastian Vettel have won more in a single campaign - Hamilton stands on the brink of setting a new British record.

At present Hamilton is tied with Nigel Mansell on 31 career wins, and given his form and that of Mercedes, it is inconceivable he will not create a new benchmark at some stage this season.

Such a feat, however, matters little to Hamilton whose focused sights are on one particular goal.

"Records are something you look at later," Hamilton said.

"For example I was the youngest champion ever in Formula One. That is something every now and then I look back on and think 'wow!'

"But currently I'm thinking about the world championship, and I honestly feel like I'm going for the first.

"But I feel so much better prepared than I ever was, with maturity, knowledge and experience paying off."

On Sunday, Hamilton could become the first British driver since Mansell in 1992 to win five successive grands prix.

The Circuit of the Americas track is certainly one he loves after triumphing at the inaugural event in 2012.

"We still have three races left to decide the drivers' championship, starting in Austin, which is one of the best weekends of the year," said Hamilton.

"A lot of the American side of my family come to the race, plus 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, hopefully ending up with another Stetson hat (given out to the winner) on the top step of the podium."

The race, however, has become overshadowed by the fact in the space of the past few days Caterham and Marussia have been forced to enter administration.

With both teams allowed to miss the next two races whilst the companies behind their administration attempt try to find new buyers, it means for the first time since the 2005 Monaco Grand Prix there will only be 18 cars lining up on the grid.

For qualifying there is every possibility just 17 will take part as outgoing champion and last year's race-winner Vettel, will require a sixth engine this season for his Red Bull.

Under the regulations that necessitates a 10-place grid penalty, leaving the team to weigh up whether to skip qualifying altogether and start Vettel from the pit lane.