Valencia - Honda rider Marc Marquez, who needs only an 11th-place finish to secure a fourth MotoGP world title this weekend, recorded the sixth best time in practice on Friday for the Valencia Grand Prix.
In the second session, the Spaniard crashed for the 26th time this season, coming off on the second turn but without suffering any serious consequences.
Marquez finished the day 0.603 of a second behind compatriot Jorge Lorenzo.
The Ducati rider recorded a best time of one minute and 30.64 seconds with another Spaniard, Dani Pedrosa of Honda, second best, 0.122sec back.
"Our pace this morning, on a medium rear tyre, was good and in the afternoon I felt well on a soft rear, despite a small crash during my last lap when I was pushing a little bit more," said Marquez.
"It was important to start the weekend well, and I feel good on the bike, so we'll try to keep this momentum going until Sunday."
Italian Andrea Dovizioso, who is Marquez's closest title rival but 21 points adrift, recorded the third best time on his Ducati.
Conditions improved during the day and the best times were recorded in the afternoon.
Dovizioso, who like Marquez has won six races in 2017, said that whatever happens on Sunday in the season-finale it had been a season to remember.
"I wouldn't have believed I'd be in this situation," the Italian told the pre-race media conference.
"And no one watching the races expected it. That's why I'm so happy and proud of what we've achieved in this championship.
"We will see - 21 points is a lot and very difficult, but it's still open. We have to focus. We have to win the race, which will be difficult, but we have good speed now. Let's see what we can do in the race. We have one strategy: try to win."
Valencia Grand Prix combined first and second free-practice times on Friday:
1. Jorge Lorenzo (ESP/Ducati) 1min 30.640sec, 2. Dani Pedrosa (ESP/Honda) at 0.122sec, 3. Andrea Dovizioso (ITA/Ducati) 0.309, 4. Andrea Iannone (Ita/Suzuki) 0.405, 5. Johann Zarco (FRA/Yamaha Tech3) 0.414, 6. Marc Marquez (ESP/Honda) 0.603, 7. Jack Miller (AUS/Honda Marc VDS) 0.717, 8. Cal Crutchlow (GBR/LCR Honda) 0.743, 9. Michele Pirro (ITA/Ducati) 0.773, 10. Pol Espargaro (ESP/KTM) 0.798, 11. Valentino Rossi (ITA/Yamaha) 0.848, 12. Maverick Vinales (ESP/Yamaha) 0.984