McLaren's Lando Norris said he was probably not ready to challenge Max Verstappen for the Formula 1 title this season and accepted that his hopes were effectively over after a demoralising defeat in Brazil earlier this month.
The Briton told reporters on Wednesday ahead of the Las Vegas Grand Prix that the race at Sao Paulo's Interlagos circuit had been a bitter blow. Norris started on pole but finished sixth while Red Bull's Verstappen went from 17th to first.
Verstappen will be crowned world champion for the fourth year in a row if he beats Norris in Las Vegas this weekend.
"It was a defining moment for the championship. The doors are almost shut," said Norris, now 62 points behind the triple world champion with three rounds remaining.
"For a week, I was pretty down after Brazil because I had that realisation of things are pretty much out of my control now, not within reach necessarily.
"That's a tough realisation when hopes and your belief is so high. For it to get knocked down so much all of a sudden was pretty demoralising and not the best of feelings. But you learn to accept that's life."
Norris hoped to enjoy the remaining races more and said he would be stronger next season.
"I probably wasn't outright ready to go up against Red Bull and Max. I think I am now and it's probably too late to do that," added the 25-year-old, who took his first win in Miami in May.
"Maybe other drivers in the past were ready for such an occasion but no one has gone up against Max so early on in their career, halfway through the season, and put up a pretty reasonable fight.
"I'm there but there's no one else doing it. I've done my best, I've not done well enough and I've always admitted that, and I think Max is probably one of the best drivers ever in Formula 1.
"I don't think you'll probably get a much better driver than Max in Formula 1 ever again ... for me to fight against that person that I know is so good, takes a bit more than what I've probably achieved this season.
"But I think what I've done since the summer break is closer to what I need to be and I think that is close to being good enough to fighting for it next year."
McLaren lead Ferrari by 36 points in the constructors' championship and Norris said the team would always come first when asked about priorities for the remaining races.