Honda's MotoGP leader Marc Marquez had a huge crash and was taken to hospital on Friday before returning to set quick laps in practice for what promises to be a title-deciding Thai Grand Prix.
The Spaniard, 98 points clear of closest rival Andrea Dovizioso with five races remaining and a sixth title beckoning, ended the day's second session at the Chang International circuit sixth fastest.
Marquez was flung off his bike after losing the rear with 10 minutes to go in the first session, landing heavily. He stayed down for a while, struggling to breathe, while the Honda was badly damaged.
He was taken to the circuit medical centre and then to hospital in nearby Buriram for checks before being cleared to continue.
"Fortunately he is OK," Repsol Honda team boss Alberto Puig told reporters. "We went to the hospital and they did an MRI and everything looks fine.
"Of course, he had some contusions in the back and also in the leg, and also here in the hip a little bit, but nothing to be worried about. We were lucky for today.
"We will continue with the plan and he will have some treatment probably, some massage or something," added the Spaniard.
Puig said the rider had been on the outside line and the tyre probably picked up some dirt.
When Marquez returned to the track he was fastest for a while before slipping down the order as the Yamahas found their pace.
French rider Fabio Quartararo topped the timesheets at the end of the day for Petronas Yamaha, ahead of factory Yamaha rider Maverick Vinales and Petronas team mate Franco Morbidelli.
Australian Jack Miller was fourth quickest for Pramac Ducati, ahead of Yamaha's Italian great Valentino Rossi. Dovizioso was eighth.
Marquez will take the title, his fourth in a row, on Sunday if he scores two points more than Dovizioso.
The Spaniard won from pole position in Thailand last year and also set the fastest lap of the race. Dovizioso finished second.