Valtteri Bottas edged Lewis Hamilton as the Mercedes drivers finished comfortably clear of the chasing pack during opening practice in Japan.
With final practice cancelled, and qualifying shifted to Sunday due to the impending arrival of Typhoon Hagibis, it placed a greater importance than usual on the opening session.
All the teams undertook several runs on various compounds, with Bottas winding up on a time of 1:28.731s, as he finished 0.076s clear of team-mate Hamilton.
Only Ferrari’s Sebastian Vettel got within a second of Bottas’ best effort, lapping the figure-of-eight circuit 0.989s slower than the Mercedes driver.
Charles Leclerc was a further two-tenths back in fourth place, while Red Bull took fifth and sixth respectively, Max Verstappen three-tenths in front of Alexander Albon.
An electrical issue stranded Carlos Sainz Jr. on the pit straight on his installation lap but McLaren quickly rectified the setback and he continued his programme, placing seventh.
Racing Point displayed encouraging pace as Sergio Perez and Lance Stroll classified eighth and ninth respectively, leaving Lando Norris to round out the top 10 for McLaren.
Romain Grosjean was next up for Haas, ahead of Alfa Romeo’s Kimi Raikkonen and the Renault pair of Nico Hulkenberg and Daniel Ricciardo, with Kevin Magnussen 15th.
Toro Rosso handed a first Formula 1 outing to reigning Super Formula and Super GT champion Naoki Yamamoto, who has had a lengthy relationship with Honda.
Yamamoto finished 17th, just a tenth of a second behind Toro Rosso counterpart Daniil Kvyat, as he completed 30 laps in the STR14, albeit with Kvyat's best effort coming on Mediums.
He became the first Japanese driver to participate in an official Formula 1 session since Kamui Kobayashi’s final outing in 2014.
Williams was 18th and 19th, with George Russell seven-tenths of a second ahead of Robert Kubica, while a suspected hydraulics problem limited Antonio Giovinazzi to just four laps.
Second practice at Suzuka is scheduled for 14:00 local time