By Steve Keating AUSTIN, Texas (Reuters) - Red Bull's quadruple world champion Sebastian Vettel won the U.S. Grand Prix on Sunday to become the first Formula One driver to take eight consecutive victories in a single season. Starting from pole, the 26-year-old German was again in a class of his own, taking the chequered flag 6.2 seconds clear of Frenchman Romain Grosjean in a Lotus. Vettel's Australian team mate Mark Webber finished a close third in the penultimate race of his grand prix career and last in America. The champion, who clinched his fourth straight title in India last month, is now one step away from equalling compatriot Michael Schumacher's 2004 record of 13 wins in a season after collecting his 12th of the year. Click here to read full news..