World champion Jenson Button says he will fight for this year's championship until the very end, even if his title chances are all but over.
The McLaren driver finished a disappointing 12th at the Korean Grand Prix last weekend, after he struggled for pace from qualifying.
The result left Button 42 points behind championship leader Fernando Alonso, with just 50 available in the two remaining races.
Although his chances of retaining his crown are extremely slim, Button says he would regret it for the rest of his life if he didn't fight until the final moment.
"I've always said that I will fight until it's mathematically impossible," said Button on his website on Thursday.
"Sure, looking at it written down on paper, you've got to admit it's a long-shot - but I'd regret it for the rest of my life if I chose not to go for it, and then circumstances transpired to give me a full run at the title.
"So, for me, the situation's the same: I'll be fighting until it's no longer possible for me. In Formula 1, you just never know - it's totally possible that I could win at Interlagos, take home maximum points and have none of the other title contenders finish. If it's another wet race, that could easily happen.
"Basically, you learn early on in this sport that it's not over until it's over."
Button said McLaren is continuing with its development push for the final two races of the season, and he reckons the team should be competitive in the next grand prix in Brazil.
"Our performance has been a little bit up and down recently. We nearly had the pace to win in Monza, we looked faster than the Red Bulls in Singapore, and our race pace was very good at Suzuka. So it's difficult to say precisely where we are.
"In Korea, we looked extremely quick during all the practice sessions, only to see that pace narrow in qualifying and the race. So I think we have every reason to still feel optimistic.
"For Brazil, we're bringing more updates to the car. That's something that's always impressed me about this team - the pace of development is just incessant, and everybody is so determined to make the car faster. We're always trying out new parts, and making changes.
"We haven't backed off the development stream just yet, so, once again, we're hopeful of another step forward in performance for Brazil. It's a track that should suit us, so I'm already looking forward to it."