Valtteri Bottas led a Mercedes one-two in Practice Three at the Japanese GP but saw his session ended by a brush with the barriers, while Ferrari's Kimi Raikkonen crashed heavily.
Bottas posted a 1:29.055 to lead team-mate Lewis Hamilton by just one hundredth of a second, while Sebastian Vettel was third, three tenths off his championship rival despite being on the quicker supersoft tyre.
But Bottas undid his impressive start by hitting the barriers on the exit of Spoon. The Finn strayed onto the damp Astroturf which twice pitched his car into the wall, causing damage to the right side of his car.
"It just went over the kerb, touched the wet grass and just lost control," Bottas, already facing a five-place grid penalty for a gearbox change, explained to Sky Italy.
"You try to use all the track available, but it's such a fine line and it's my mistake."
His mistake had brought out the red flag and just a minute after the session resumed, Raikkonen crashed after losing control at the second Degner.
Max Verstappen headed Red Bull team-mate Daniel Ricciardo in fourth, eight tenths down on Bottas' time while Esteban Ocon was sixth for Force India.
Fernando Alonso was an impressive eighth for McLaren-Honda, but the Spaniard is set to start Sunday's race last after a 35-place grid penalty for an overnight engine change.
Qualifying starts at 7am with coverage underway from 6am on Sky Sports F1.