Lewis Hamilton top in Japanese GP first practice
Lewis Hamilton set an imposing pace as Mercedes impressed in first practice at the Japanese Grand Prix.
The world championship leader was 0.446 seconds quicker than team-mate Valtteri Bottas - and 0.682secs quicker than Red Bull's Daniel Ricciardo in third place.
Hamilton was using softer tyres than Bottas - but earlier in the session had been just 0.183secs slower than the Finn using tyres one step harder.
Hamilton also narrowly avoided a huge crash with Toro Rosso's Pierre Gasly.
The Frenchman was going 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.
There was also a rare mistake from McLaren's Fernando Alonso, who went off at high speed on the entry to the difficult Degner One corner when he put his outside wheels on the grass on entry.
Alonso speared off into the gravel trap and spun, but was able to rejoin the track.
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Vettel was a huge 0.994secs slower than Hamilton despite using the fastest super-soft tyres for his quickest lap and for much of the session.
Hamilton's fastest time was set on the soft tyre, while Bottas was using the medium when he went second fastest and Ricciardo the super-soft for his time.
Watching out on track at the demanding Esses section early in the lap, the Mercedes and the Red Bull looked especially poised and dramatic through the high-speed changes of direction.
Ferrari's Kimi Raikkonen was fourth fastest, ahead of Vettel and the second Red Bull of Max Verstappen.
And there was an accomplished performance from Sauber's Charles Leclerc.
The Monegasque, who is being promoted to Ferrari next season, has never driven at Suzuka before but was quickly up to speed, 0.3secs quicker than team-mate Marcus Ericsson within three flying laps, and a further 0.1secs ahead before the usual break in the session after 40 minutes.
Leclerc ended the session ninth, behind Force India's Esteban Ocon and Haas driver Romain Grosjean, and 0.144secs quicker than Ericsson.