WASHINGTON, Oct. 20 -- Lewis Hamilton registered the fastest laps in both free practice sessions of the F1 US Grand Prix on Friday as the Mercedes driver is closing to winning his fourth drivers' title.

The 32-year-old Britain had a best lap in the first free practice with one minute and 36.335 seconds to outpace title rival Sebastian Vettel of Ferrari by 0.593 seconds. Hamilton's teammate Valtteri Bottas was third.

Hamilton then kept his top form in the second practice session to clock a time of 1 minute and 34.668 seconds. Red Bull's Max Verstappen was second, 0.397 seconds behind. Vettel was third.

"It's been an interesting day with lots of ups and downs in terms of how the track has moved around and how the car feels. But overall the car was feeling good. There are lots of areas we can improve on, but generally it feels like a solid platform and a solid start to the weekend," said Hamilton.

"It was amazing to have so much support from the fans here. I have a lot of support out here, which I am super grateful for. I'm excited to see everyone tomorrow," added the Briton, who won here in the past three seasons.

In the drivers's standings, Hamilton leads on 306 points, 59 more than second-placed Vettel. Hamilton will seal the title in Sunday's race if he can win and Vettel fails to finish in the top five.

James Allison, Mercedes' technical director, said of the free practice: "That's a promising start to the weekend, we are generally quite happy with the car, but we are also conscious that Ferrari had a bit of a troubled day today, so maybe we haven't yet really seen where the opposition are at."