Sebastian Vettel issued an early warning to Fernando Alonso that he is not prepared for their title fight to go down to the wire.
In the opening practice session at the £250million Circuit of The Americas that plays host to the first United States Grand Prix for five years, Vettel left his rivals in the shade come the end.
The 25-year-old Red Bull star, who is currently 10 points clear of Alonso in the driver's championship, finished 1.418secs clear of Lewis Hamilton, the biggest margin at the end of any practice session this season, with Alonso 2.212secs adrift in his Ferrari.
It is, of course, still early days on a track still very green and needing to be rubbered in, but as a potential marker, it will have had an effect.
Vettel needs to finish 15 points clear of Alonso on Sunday to become only the third driver in Formula One history - Juan Manuel Fangio and Michael Schumacher the others - to claim three titles in a row.