Lewis Hamilton was in scintillating form as Mercedes dominated Friday practice at the Japanese Grand Prix.
He was 0.833 seconds clear of title rival Sebastian Vettel's Ferrari, and 0.461secs faster than team-mate Valtteri Bottas at the Suzuka track.
Hamilton was even faster on the 'soft' tyre, the middle compound this weekend, than Vettel was on the fastest 'super-soft'.
The Briton also narrowly avoided a huge crash in first practice.
Frenchman Pierre Gasly was driving his Toro Rosso slowly on the racing line at the chicane and Hamilton had to take avoiding action and run into the escape road as he closed in at a frightening speed.
The two drivers were summoned to see the stewards to discuss the incident, where officials handed Gasly a reprimand.
Hamilton was fastest in the first session, when he was 0.446secs ahead of Bottas and 0.682secs quicker than Red Bull's Daniel Ricciardo in third.
'I'm having the best day'
Hamilton's pace was reflected in his mood. He said over the radio: "This track is awesome. I'm having the best day."
His pace continued the impression that Mercedes have made a dramatic step forward in performance following the end of the European season.
At the Italian Grand Prix in early September, Ferrari locked out the front row of the grid, but that was the last of a series of races dating back to the German Grand Prix in late July when the Italian team appeared to have the fastest car.
Mercedes took a surprise step forward last month in Singapore, a track that had traditionally been a bogey circuit for them, and Hamilton took pole and a dominant win.
Mercedes then locked out the front row in Russia last weekend, when Bottas handed Hamilton the win to make it four victories in the past five races for the Briton.
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What about race pace?
Although it is only Friday practice, and form does not always translate into qualifying and race, the performance on the first day of the Japanese Grand Prix was disheartening for Ferrari.
Not only were they close to a second lap slower than Mercedes in qualifying time, Hamilton also had a huge advantage on their race-simulation runs, where Hamilton was 0.7secs quicker than Vettel on the super-soft tyre.
However, the gap is so large that most will assume something else is at play - and that perhaps Ferrari have their engines turned down for reliability purposes on Fridays when it does not matter.
Hamilton starts the weekend in Japan with a 50-point championship lead, and can win the title by finishing second in all the remaining races, and third in a couple, even if Vettel wins them all.
But the sort of form Mercedes showed on Friday at Suzuka, one of the world's greatest race tracks, suggests any hopes Vettel might have of somehow getting back on terms with Hamilton are dim indeed.
What they said
Hamilton said: "Suzuka has to be one of my favourite circuits, if not the favourite one - it's very cool. Especially the first and second sectors are insane, the first section is the best roller coaster ride that I've felt in a Formula 1 car.
"The balance was in quite a nice place, so I was just enjoying it. Every year I come back, there are always areas that I can improve, so I was like: 'There are two or three corners where I know that I need to kill it this year,' and I got straight up to it. I was much better than I had ever been through those particular corners.
"I'm just loving driving more than ever; when you get in the car, it's just the best."
Vettel said: "I don't think we tried something different to other Fridays. We know what the car can do and we need to focus on that to try to get everything out to put us in the best possible position. If we can grasp pole, great, but if not we need to be right behind."
Both Ferraris were suffering from blistered tyres on their long runs, and Vettel said: "We were sliding a little too much and when you slide, the temperatures go up and blistering is caused by sliding and we were probably damaging the tyres more than others.
"It has been a clean Friday, no issues with the car. We focus on our work and we try to squeeze everything that is left in the car."
Best of the rest
Max Verstappen was the fastest Red Bull in fourth place, a second off the pace.
Behind the top six, Force India's Esteban Ocon was best of the rest in seventh, ahead of Haas driver Romain Grosjean, Sauber's Marcus Ericsson and Toro Rosso's Brendon Hartley.
McLaren did not run on the fastest super-soft tyre because they have chosen to bring only four sets to Japan for each driver - three fewer than anyone else.
Fernando Alonso was 17th fastest and team-mate Stoffel Vandoorne slowest of all, a second off the Spaniard.
Who will win in Japan?
Choose your top three drivers from the list below