British driver Jenson Button of McLaren Mercedes takes a turn during the qualifying round of the United States Formula One Grand Prix in Austin, Texas on November 1, 2014 (AFP Photo/Jim Watson)

Sao Paulo (AFP) - Jenson Button is ready to make a dignified exit from Formula One and says he has nothing to prove after finishing a typically smooth fourth in Sunday's Brazilian Grand Prix.

The 2009 world champion, set to be replaced by two-time champion Fernando Alonso at McLaren next year, said he felt he remained capable of racing at the highest level.

The 34-year-old Briton said: "I feel I'm doing a pretty good job at the moment. I've got nothing to prove and this is what I've done for 15 years.

"I'll always do my best and sometimes it isn't enough but here it was.

"I think I've had 'it' since I was 20 years old -- and I think my experience showed today.

"I'm really happy with P4 - you always want more to challenge for the podium - and we thought we were sort of playing with the Williams at one point but it wasn't the case.

"I enjoyed the race, a great battle with Kimi (Raikkonen) and to beat both Red Bulls, both Ferraris and a Williams is not a bad day's work.

"That's all I can do right now, go out there and enjoy my racing and I loved it out there. You have good days and you have bad days when you're in the situation I am (in), in terms of mentally, but I don't think any of the days on the circuit have been negative, they've always been positive so I'm happy."

Button declined to discuss his future - a decision on Alonso leaving Ferrari for McLaren has yet to be announced -- but made clear he wished to continue racing.

"I'm not ready to stop racing, no," he said.

"I'm here to race, do the best job I can which is what I try and do every weekend. Sometimes it doesn't work out but most of the time it does.

"All you've got to do is drive the car as fast as you can and carry yourself as well as you can. That's all you can do and the rest isn't in your hands."