Alpine's Pierre Gasly brought Friday practice to an early end at the Japanese Grand Prix with a crash as Max Verstappen dominated the day.
He lost control at the notorious Degner Two corner, locking a front wheel before sliding off the track and ripping off a front wheel on the barrier.
Verstappen ended the day 0.320 seconds quicker than Ferrari's Charles Leclerc and looking close to unbeatable.
McLaren's Lando Norris was third ahead of Carlos Sainz's Ferrari.
George Russell managed fifth on what appeared to be a difficult day for Mercedes and certainly was for Lewis Hamilton who was down in 14th place and 0.501secs slower than his team-mate.
Aston Martin's Fernando Alonso was sixth fastest ahead of Williams' Alex Albon and the McLaren of Oscar Piastri. Red Bull's Sergio Perez was ninth, a second off Verstappen, and Alfa Romeo's Valtteri Bottas 10th.
Gasly had an accident that several other drivers had been threatening to have all day.
Degner Two is arguably the most difficult corner at the most demanding track on the calendar. It is preceded by the Degner One, a much faster bend, and drivers have to break for the second corner straight after flicking through the first.
It is a corner where accidents are common, and Hamilton, Williams' Logan Sargeant, and Alfa Romeo's Zhou Guanyu all ran wide over the kerb there during the day but managed to stay in control.
Gasly's accident was different. Locking his inside front wheel on the way in, he slid wide and onto the kerb, and once into the gravel a crash was almost inevitable as the run-off area was so short.
Overall, Verstappen looked imperious. He made a flying start to the first session, lapping well over a second clear of the field, and two seconds ahead of Perez.
The Dutchman appeared set on delivering a message, five days after Red Bull was defeated in Singapore - the first time they had lost a race all season.
Amid speculation in the paddock that their performance at Marina Bay could have been influenced by a technical directive clamping down on flexible floors, Verstappen was in imposing form from the moment he took to the track.
Verstappen's progress on Friday suggested those claims were wide of the mark.
As usual, his advantage over a longer run was even more pronounced - he was about a second a lap faster on average than anyone else on the race-simulations runs late in the second session.
Behind him, Leclerc was next fastest, comfortably ahead of Sainz, with both running Ferrari's new floor in the second session after Leclerc tested it in the first.
The Spaniard was nevertheless quicker than Perez. On the soft tyre, Norris was fastest, ahead of Alonso, who was neck and next with Russell, with Hamilton again trailing, although not by as much as over a single lap.
