Toro Rosso driver Carlos Sainz emerged as the fastest driver, while reigning world champion Lewis Hamilton finished fifth in the rain soaked first practice session at the Japanese Grand Prix in Suzuka on Friday.
The rookie Spaniard was 0.504 seconds quicker than Red Bull driver Daniil Kvyat to lead a session for the first time in his 14 race career, Sport24 reported.
Hamilton spent most of the time in the garage and completed only six laps, while his nearest championship challenger and Mercedes team mate Nico Rosberg was third, ahead of Ferrari's Sebastian Vettel on full wet.
Hamilton heads into Japanese Grand Prix holding a 41 point-lead over Rosberg.
Meanwhile, four-time world champion Vettel will aim to sustain the momentum and stamp Ferrari's authority after winning the previous race in Singapore.