Vettel lays down marker

Sebastian Vettel maintained his total domination of practice at the United States Grand Prix on Saturday morning when he topped the times for Red Bull for a third successive session ahead of Sunday's showdown, his 100th race in Formula One.

Sebastian Vettel maintained his total domination of practice at the United States Grand Prix on Saturday morning when he topped the times for Red Bull for a third successive session ahead of Sunday's showdown, his 100th race in Formula One.

The 25-year-old German, who needs to outscore nearest rival Fernando Alonso of Ferrari by 15 points to become the youngest triple champion in F1 history, clocked a fastest lap in one minute and 36.490 seconds to emerge fastest.

That was enough to leave him nearly three-tenths of a second clear of nearest challenger Lewis Hamilton who, in his penultimate race weekend with McLaren before joining Mercedes next year, recorded a best time of 1:36.748.

Both men clocked their times in a busy final flurry of activity in the final minutes of the hour-long session run in cold conditions, but in front of a big crowd dressed in winter jackets, at the new Circuit of the Americas 25 kilometres out of downtown Austin. Venezuelan Pastor Maldonado was third fastest for Williams.