Lewis Hamilton apologised to his Ferrari team after overriding the pit wall and choosing his own strategy during the Singapore Grand Prix.
Ferrari were on course to finish second and third with Charles Leclerc and Hamilton, but instead the seven-time champion fell back to sixth in the closing laps as he fought a losing battle to hold off three cars while on fading tyres.
Hamilton apologised to the team over the radio on the slowing-down lap after the race, saying: "Sorry, boys. I let you down today with that strategy. My call, and I lost us valuable points. I'll try and make up for it in the next one."
Team principal Frederic Vasseur said: "Clearly we asked them to pit. Charles pitted. Lewis didn't want to pit because he... I don't know why. And then he realised it was the wrong call. It's why he apologised to the team.
"Now it's not a drama for me that he made the wrong call. I'm making mistakes, he's making mistakes, we're all making mistakes sometimes. Now we have to look ahead and make mistakes positively."
Hamilton did not speak to the media after the race after saying he felt unwell and being given permission to miss the interview zone, known as the media pen.
In a statement released by Ferrari, he said: "Under the virtual safety car, the team called me in but I missed the entry. After that, I decided to stay out and try to hold track position to the end but in the closing laps, I was struggling massively with tyre degradation and lost three places, finishing P6, which doesn't reflect the pace we had in the car.
"A painful lesson, but I take full responsibility for the decisions I made. Not every call will work out, and I can accept getting it wrong but I'm sorry for the team for the points we lost today. They put so much into every weekend, and I wanted to deliver more for them. I'll continue to put the work in and come back fighting at the next race."
Ferrari called both cars in to the pits during a virtual safety car that was called mid-race. Stopping under the VSC saves about 10 seconds versus stopping under racing conditions.
Hamilton said in the statement that his decision was based on his improved pace on the soft-compound tyre after he had been forced to make an earlier pit stop than planned because the medium tyre on which he started the race was not performing.
"At a track (where it's) difficult to overtake, you need to try something different and I chose to start on a new medium tyre, to go long and try to make a one-stop work," he said.
"Unfortunately the medium didn't perform as well as the soft. I had a good second stint and the pace was back, but I couldn't make the progress I needed."
His first stop was six laps before Leclerc's and when the Monegasque emerged back on to the track, Hamilton was right behind him and was initially faster.
At one stage, he pointed out to the team that he had "lost two seconds on that lap", but the team decided not to invert the cars. Hamilton followed Leclerc within two seconds for a further 10 laps before slowly starting to lose ground a couple of laps before the VSC.
Vasseur said the team decided to leave Leclerc in front because he had pitted later than Hamilton.
"The tyre advantage was for Charles, that he pitted six laps later," Vasseur said. "I think it was the right call."
However, that argument appears to be somewhat undermined by the fact that the medium tyre emerged as the worst option for the race - as Hamilton had found out in the first stint and other drivers found later on.
Leclerc was put back on the soft when he stopped under the VSC.
Hamilton's error means Mercedes driver Kimi Antonelli is in a position to clinch his first world title at the next race, the US Grand Prix in Austin, after finishing third behind race winner Max Verstappen and Leclerc.
Antonelli's lead over team-mate George Russell, who finished ninth after starting from the back of the grid, has extended to 102 points and 111 over Hamilton.
The Italian needs to leave Austin with an advantage of at least 125 points to clinch the title, with five races at most remaining after that.
He will do so if he wins the race with Russell finishing ninth or lower and Hamilton fifth or lower at the Circuit of the Americas on 25 October.
If he becomes champion this year, the 20-year-old will be the youngest in Formula 1 history.
Asked if he would be daring to dream about the title on the flight home, he said: "For sure, but at the same time, I know it's very close, I know it's there, but I just need to make sure that I keep doing the best I can.
"The mindset is always the same, to go out there and win and perform the best way I can.
"This weekend I haven't particularly driven that well. I felt like I could have done a better job, but I feel confident that a week to reset and I'm really looking forward to being back in Austin.
"But at the end of the day, if I don't do my job well, then the result won't come. So in order to achieve what I want, I need to perform, as simple as that."
There is some doubt about the mathematics of the championship because it is not completely clear how many races are remaining.
F1 is pushing ahead with the original schedule, which ends with two races in Qatar and Abu Dhabi, despite the war in the Middle East, having been reassured the countries are safe.
But if the war intensifies before mid-November, those races will have to be cancelled. In that event, the season would end at Imola in Italy, on the same 6 December date as Abu Dhabi, after a two-week break following the Las Vegas race on 22 November.
Mercedes team principal Toto Wolff said: "I haven't looked at it from that perspective, because the moment I have the thought of 'how many points is it actually, and when could he win it,' I remind myself that this is motor racing and crazy things have happened.
"The aim must be to score points, not to lose too many on the others, like today, gaining on Lewis, which was unexpected, and then it's going to come towards him, whether that's in Mexico or Brazil (the races immediately after Austin) or further down the line."
Mercedes split their cars between two different specifications in Singapore in an attempt to understand why a major upgrade introduced at the previous race in Malaysia did not work.
Antonelli drove the new spec and Russell the old, and by the end of the weekend the team said they had made some progress in understanding the new aerodynamic package.
Antonelli said: "We're just trying to understand how to extract more potential out of it because we do see the gains, we do see what it could bring.
"It's just that the window is very small at the moment where the car operates and is very sensitive to the way you drive it, the way you take a corner, the way you brake. So it reacts very differently.
"So hopefully now in Austin, we have three free practices, so we can be very open-minded with set-up and hopefully we can find a way and we can use the full potential of the package and finally see the gains."
Russell was asked how he viewed the rest of the season now the championship was almost over. He replied: "The goal is to improve the car. We were dominant for so long and since the break we have seen Red Bull be exceptionally fast on many different types of circuits and we need to go back to winning ways."
Verstappen's victory was his first grand prix win in Singapore. It was also his second in succession, emphasising Red Bull's return to the front after a difficult start to the season.
Verstappen said: "Very different tracks that we have gone well at now. That's of course always nice to see.
"Our car has taken a really nice step forward. It's just been more driveable and more predictable. That's what I wanted and needed from the car to find that last step to fight up front. And I hope that we can carry that momentum forward.
"We don't really have anything to win in the championship, right? Kimi is miles ahead. I don't care if I'm second, third or fourth. It doesn't do anything. But I just want to have fun until the end, you know, try to go for a day's success."
But the four-time champion was cautious about the prospect of being competitive at every race before the end of the season.
"It's very difficult to say and I don't want to say now that I will be in the fight in Austin," he said.
"Yeah, the last few weekends have been great. But I just take it race by race and once we are in Austin, then we'll see how it will go there. But it's again a very different track.
"From what I saw in WEC (the World Endurance Championship), the track is incredibly bumpy. Oh my God, yeah, I'll probably need to order a new spine, I think, after the weekend. Yeah, I'll become like Robocop. Yeah, crazy. That's again a new challenge for everyone, to deal with those bumps.
"And then we just go from there. We have to go to Mexico, high altitude, everything will run super hot, and we need to see how the engine is going to perform in that altitude, how the car is behaving, because it's very different.
"So there are so many different things that you can get right or wrong in those races."