Mark Webber has said that Sebastian Vettel needs to wrap up the Formula 1 drivers' title in the penultimate race of the season.
The reigning world champion will keep the title if he secures 15 points more than Fernando Alonso at the United States Grand Prix in Austin on Sunday.
Vettel's Red Bull teammate told Australian newspaper The Age: "Clearly, Austin's a very important weekend because Brazil can throw up some 'funnies'.
"There can be a bit of rain around there, so that's a bit more of a nervous venue. I'm not saying it can't rain at Austin, but Brazil can be incredibly inconsistent with the weather, so that might come into the mix."
Red Bull can also win the constructors' title this weekend.
