Porsche led home favourite Toyota in a red-flagged opening practice for this weekend’s World Endurance Championship round at Fuji.
Laurens Vanthoor set a best time of 1m30.581s in the #6 Porsche 963 LMDh at the very beginning of the 90-minute session to head the #8 Toyota GR010 HYBRID of Ryo Hirakawa by just 0.010s.
Third place went to Antonio Fuoco in the Le Mans 24 Hours-winning #50 Ferrari 499P, but the Italian trailed the leading two cars by almost half a second with a time of 1m31.104s.
Frederic Makowiecki claimed fourth in in the #5 Porsche, the French driver making a relatively late improvement to demote the #7 Toyota of Nyck de Vries to fifth place.
The #83 customer AF Corse Ferrari took sixth in the hands of Yifei Ye, while Stoffel Vandoorne guided the #94 Peugeot 9X8 to a strong seventh place ahead of Ferdinand Habsburg in the best of the Alpines, the #35 A424.
The top 10 was completed by the #12 Jota Porsche of Will Stevens and the #51 Ferrari driven by James Calado.
Cadillac finished a distant 12th with Earl Bamber ending up almost a second off the best time set by Vanthoor. The American marque separated the two BMW entries, the #15 car finishing ahead in 11th place.
The #63 Lamborghini shared by Mirko Bortolotti, Daniil Kvyat and Edoardo Mortara was classified 17th, only ahead of the #38 Jota Porsche in the Hypercar class.
McLaren quickest in LMGT3
In the LMGT3 class, Marino Sato ended up fastest in the #95 United Autosports McLaren 720S GT3 with a best lap of 1m40.528s.
However, the sister #59 McLaren driven by Gregoire Saucy caused the only major interruption of the session when he stopped at the Dunlop chicane with 21 minutes left on the clock.
The car could be recovered quickly, with green flag being waved with 14 minutes remaining.
Alessio Rovera set an identical time to Sato in the #55 AF Corse Ferrari 296 GT3 to finish second, with Davide Rigon finishing another two tenths behind in the sister Ferrari to claim third.
The best of the rest was Franck Perera in the #60 Iron Lynx Lamborghini Huracan GT3 Evo with a best effort of 1m40.849s.