Sebastian Vettel has hit out at the penalty that has further dented his small chances of keeping his championship hopes alive.
In Austin, where Lewis Hamilton can mathematically clinch the title, Vettel has been penalised 3 grid positions for not slowing down enough for a red flag.
"I saw the flag and went off the gas, but not enough in the stewards' eyes," said the Ferrari driver after practice.
"In my opinion it's wrong. I slowed down, I looked around. I should have slowed to 30kph but then maybe a car behind me would have crashed into me, and what's the point of that?
"The stewards disagree, there's nothing more to say about it," Vettel added.
2016 world champion Nico Rosberg said the penalty is a "shame".
"His car was fast enough for the title," he told the German broadcaster RTL.