Ferrari's Fernando Alonso has admitted he needs to be "very, very lucky" to prevent Red Bull's Sebastian Vettel winning the title this year.
Alonso finished second in Sunday's Singapore Grand Prix to the Red Bull driver and is 60 points behind with 150 available in the remaining six races.
Alonso said: "We have to be realistic. We have to be honest with ourselves and say we need a lot of luck.
"It is a tough opponent, but if we get that luck we will get there."
The 32-year-old Spaniard admitted he needed Vettel to hit problems in more than one of the remaining races.
The next is in Korea on 6 October, followed by Japan, India, Abu Dhabi, the USA and Brazil.
"We don't just need luck in Korea," Alonso said. "We need it in Korea, Japan, India, Abu Dhabi.
"We will try to improve the car every race but it is not enough. Our opponents are doing a better job. In sport the best one wins and we are not the best ones at the moment, so we will keep working."
Alonso pointed to the retirement of Vettel's team-mate Mark Webber on the final lap in Singapore as a reason for hope.
"We have a points deficit that is a big distance and a performance deficit that is a big gap," he said.
"Webber stopped in the last lap, if this happens to Sebastian one weekend we have to be there in second place. But being realistic we know we need to be very, very lucky."
Red Bull team boss Christian Horner said they would keep pushing to try to secure the title as early as possible - and admitted for the first time they were likely to do so before end of the season.
"It's my job to worry," Horner said. "You can't become complacent in any way.
"We never have yet and we won't this year. Our approach is one race at a time.
"Next challenge is Korea, get the most out of that venue and after that Suzuka. If we do that, then the championships tend to take care of themselves."