Lewis Hamilton has been cast 33 points adrift of Nico Rosberg after the Briton finished third in the Japanese Grand Prix.
Here, we look at the increasingly one-sided title battle, along with other things we learned from the 17th round of the championship in Suzuka.
1. Nico Rosberg has upped the ante.
Hamilton was already on the back foot heading to Japan and, following a curious display from the world champion both on and off the track, his quest to win a fourth title is now out of his hands. He could win each of the four remaining races - in the United States, Mexico, Brazil and Abu Dhabi - and still come up short.
So, what has gone wrong for Hamilton?
Two crushing victories in the last three races have left him bewildered and confused. The Briton also seems thrown by his own belief, however wild, that Mercedes could be sabotaging his campaign. And his erratic display in the pre-race press conference, and subsequent refusal to speak to the written media, are off-track distractions that he did not need to create.
Mercedes boss Toto Wolff has backed his driver to bounce back in Austin, Texas, but judging by Hamilton's demeanour it seems that may not happen.
2. Lewis Hamilton may have to think outside the box.
With the title race now out of his hands, Hamilton may be be forced to explore a range of different tactics to prevent Rosberg from winning his maiden title. The German can afford to finish second three times and third once, and still secure the crown.
But Wolff will not be relaxing the team's rules of engagement despite winning the constructors' championship in Japan and with the drivers' title heading to either Rosberg or Hamilton. He said: "If we started to tweak certain details it would open up a can of worms. We have never had team orders, so there will be no change."
3. These are tough times for Jenson Button.
In what is likely to be his last Japanese Grand Prix, Jenson Button endured a weekend to forget for McLaren. The 36-year-old, who will not be competing in Formula One next season, described his win here back in 2011 among the best of his career. But he could manage only 18th on Sunday.
His teammate Fernando Alonso, meanwhile, finished just two places better off. Button said: "I finished 18th, so it's pretty horrific. Sixteenth and 18th for us is a long way behind the points and a very tough weekend."
4. Jolyon Palmer was pleased with his progress.
Button's compatriot Jolyon Palmer scored the first point of his career in Malaysia last weekend and, while he was unable to replicate that accomplishment in Japan, the British rookie described his drive on Sunday as a better performance. Palmer, whose future in F1 beyond this season remains unclear, finished 12th in a race in which all 22 drivers got to the end.
Palmer, 25, said: "Tenth last week and 12th this week, but this week everyone finished the race. We had a lot of luck last week and I think today was actually a stronger performance."
5. Ferrari's strategy was costly for Sebastian Vettel.
Sebastian Vettel refused to take aim at his Ferrari team despite a peculiar strategy that potentially cost him the final spot on the podium.
Vettel's future with the Italian constructor beyond 2017 has been thrown into doubt by team principal Maurizio Arrivabene, who told the four-time champion to "earn" his next contract. Vettel was ahead of Hamilton on the track but Mercedes utilised their second pit stop to get Hamilton ahead of the German.
Vettel, who stopped one lap later than the Briton, said: "It's easy to analyse now and say what we could have done and when, but in the moment I think it was the right decision."