Red Bull's Sebastian Vettel has refused to get downbeat following his second-placed finish at the United States Grand Prix on Sunday.

Lewis Hamilton's victory in Texas means that the World Championship leader will have to wait until the final race of the season in Brazil next weekend to clinch a third consecutive world title.

"Now we have another step to make in Brazil," he said. "In terms of the Championship, it's looking a bit better after today."

If title rival Fernando Alonso wins next weekend's race in Sao Paulo then Vettel will have to finish in at least fourth place to seal the Championship.