Lewis Hamilton set the fastest time in second practice in the Japanese Grand Prix, beating team-mate and title rival Nico Rosberg by 0.24 seconds.
The two Mercedes drivers were in a league of their own, more than a second clear of the rest of the field.
Williams's Valtteri Bottas was third ahead of McLaren's Jenson Button and Red Bull's Sebastian Vettel at Suzuka.
The two Ferraris of Kimi Raikkonen and Fernando Alonso were sixth and seventh respectively.
But no-one looked like they had a chance of challenging Hamilton and Rosberg at the latest stage of their tense battle for the title.
Hamilton heads into the weekend three points clear of Rosberg and the two were closely matched throughout the day and well clear of the rest of the field, whether on single-lap pace or over a race-simulation run on heavier fuel.
Hamilton appeared more competitive on the faster 'medium' tyre, which will be used for qualifying on Saturday, while Rosberg had an advantage on their race-type laps when they switched to the 'hard' tyre late in the session.
Hamilton has turned a 29-point deficit into a three-point advantage with two victories in the last two races and Rosberg's retirement in Singapore two weeks ago.
But they seem likely to have another close fight throughout the weekend at Suzuka, arguably the most demanding circuit on the calendar.
A brief shower in the closing minutes did not affect the drivers too much, but the weather is a talking point.
Qualifying is expected to be dry, but the race is likely to be wet, as typhoon Phanfone approaches the Japanese mainland.
Although the eye of the storm is not expected to hit until Monday, heavy rain and strong winds are expected on Sunday and there have been discussions about whether the start of the race should be moved. As things stand, it is likely to go ahead at 15:00 local time (07:00 BST) as scheduled.
Suzuka proved its usual test for the drivers, with Daniel Ricciardo and Kamui Kobayashi suffering worst.
Red Bull's Ricciardo had a heavy crash at the last corner, which led to the session being stopped while the car was recovered.
Earlier, Japanese Kamui Kobayashi became another driver to suffer on the notoriously demanding track, crashing after losing control at Turn Three.
The session came to an end about three minutes short of its allotted 90 minutes when Jean-Eric Vergne's Toro Rosso hit the latest in a series of reliability problems and ground to a halt on the back straight after the Spoon Curve.
The car was driven by 17-year-old Max Verstappen in the first session as the Dutchman set a new record as the youngest man to take part in a grand prix weekend ahead of his full debut in 2015.
Verstappen suffered a turbo failure with about seven minutes of the first session remaining. The car was repaired in time for Vergne to go out after about 10 minutes of the second session, only to grind to a halt again.
The Frenchman did manage some laps, posting the 11th fastest time, before the car again hit trouble.
Lotus's Pastor Maldonado will take a 10-place grid penalty for using more than the allowed number of engine components.