Title hopes pretty much over - Button (UK users only)
McLaren's Jenson Button admitted his chances of defending his world title are all but over after he finished 12th in the Korean Grand Prix.
Button is 42 points behind new leader Fernando Alonso of Ferrari with a maximum of 50 points available.
Asked by BBC Sport if he was still in contention, Button said: "Not really. Everyone else needs to have failures."
He later vowed to "keep fighting", while Lewis Hamilton put his hopes in future updates to their McLaren car.
"We can still do this," said Hamilton. "We have some stuff coming on the car which should enable us to fight with Red Bull in Brazil and Abu Dhabi."
Title not out of reach - Hamilton
Hamilton picked up 18 points for finishing second in Korea and is currently 21 points behind Alonso.
Button's initial comments came immediately after the race and he later clarified his point.
"You say lots of crazy things in the heat of the moment. I was pretty emotional when I got out of the car," said Button on BBC Sport's F1 Forum.
"But my championship, if the other guys do not have issues, failures or non-scores, then yes my championship is pretty much over.
"But you don't win championships by sitting back and saying that's it I can't win it. You fight until the end.
"Until I can't win it mathematically I have to keep fighting.
"Everybody keeps talking about Kimi Raikkonen and how he won the championship in 2007 and that's not the only time.
"That kind of thing has happened time and time again. Just look at Red Bull here, they have lost so many points.
"They could have walked away with it if they had finished one-two here.
"So it proves that it can turn around very quickly I am not saying it's going to be easy, it's a very small chance, but that's all I need to keep pushing," continued the 30-year-old Englishman.
Highlights - Korean Grand Prix
Button trails team-mate Hamilton by 21 points with two races remaining, but he insisted he would keep fighting for the title until it became impossible for him to win it.
"If Kimi Raikkonen sat back and thought he was not going to win the championship in 2007 then we would have had a different world champion. You have to push on until the end.
"If I can't mathematically win the championship I would do whatever I needed to do for the team," continued Button.
"That is just in me, that's not what I would be asked to do, that is just what you do as a driver when you can't win the championship any more."