Lewis Hamilton tops US GP practice as Sebastian Vettel given penalty

Ferrari's Sebastian Vettel has been handed a three-place grid penalty at the United States Grand Prix.

The decision, for not slowing sufficiently for a red flag in practice, increases the chances of Lewis Hamilton clinching his fifth world title in the race on Sunday.

Hamilton will be champion if he scores eight more points than Vettel.

Hamilton has won five of the last six races and topped both Friday sessions.

Vettel's offence came after the first session was stopped because Sauber's Charles Leclerc, who will be Vettel's team-mate at Ferrari next year, had strewn gravel on the track at Turn Nine when rejoining after a spin in wet conditions.

Stewards ruled that Vettel had gone faster than the minimum time permitted in that area of the track.

The decision means Vettel cannot start the race higher than fourth, even if he takes pole position on Saturday, when the wet conditions of Friday are expected to continue.

Mercedes have been quicker than Ferrari in the wet so far this season. If Vettel qualifies third, he will start the race sixth, and his chances of finishing second will be small.

Vettel said: "From inside the car, I slowed down enough. They weren't happy.

They were very specific saying I took 27.7secs to slow down. I saw the red flag, I slowed down, had a look around where the car was potentially stuck in the wall or if there was one around Turns Nine and 10, and then slowed down significantly to comply with the rules. They felt it took too long.

"There should be common sense with the rules we have. Lining out 27.7secs precisely as an act of not complying with the rules is wrong.

"The rules are clear, so we know, but it is the first time we had it in the wet and in the wet the target is a lot slower, so literally I have to stop to 30, 40, 50 km/h to bring down the delta (time in that sector of the lap).

"In my opinion it is not the right thing. If there is a car behind you it might run into you, but it is more important you don't get a penalty."

It is the latest in a series of errors committed by either the driver or his team that have badly affected their championship chances this season.

By contrast, Hamilton had a perfect day, despite the inclement conditions.

Hamilton headed Toro Rosso's Pierre Gasly by 1.012 seconds in the second session after beating Mercedes team-mate Valtteri Bottas by 1.3secs in the first.

Gasly's time was set on new tyres while those around him were on slower used tyres.

Vettel was only 11th fastest in the second session, 5.6secs off the pace. He was fifth and nearly two seconds behind Hamilton in the first.

Ferrari have brought an aerodynamic upgrade this weekend in the hope of closing the gap to Mercedes, which has opened up dramatically in the last three races.

The conditions made both sessions unrepresentative and Vettel was running on much older intermediate tyres than Hamilton in the second session.

However, Vettel said he believed Ferrari still lacked pace in wet conditions.

"Not many quality laps," he said, "but I think it's clear that when it's wet we were not quick enough today."

In the second session, Red Bull's Max Verstappen was third fastest on used tyres, ahead of McLaren's Fernando Alonso fourth ahead of Renault's Nico Hulkenberg. Toro Rosso's Brendon Hartley, using new tyres like his team-mate.

Four drivers did not run at all in the session - Bottas, Red Bull's Daniel Ricciardo and both Haas cars.