Mercedes star Nico Rosberg topped the timesheet in the first and second practice sessions on Friday ahead of this weekend's Japanese Grand Prix.
The 31-year-old currently leads the championship by 23 points with five races left in the calendar.
The German's teammate Lewis Hamilton needs to win at Suzuka in order to keep his title hopes alive, but he was 0.215 seconds slower than his rival.
Ferrari's Sebastian Vettel recorded the third-fastest time, while his teammate Kimi Raikkonen was fourth quickest, with Red Bull duo Daniel Ricciardo and Max Verstappen fifth and sixth respectively.
In the second practice of the day, Rosberg set the pace again, but he was just 0.072 seconds quicker than Hamilton.
Raikkonen's best lap was 0.323 seconds slower than the Mercedes pair, while Verstappen edged out Vettel in fourth.
