GREATER NOIDA (India)  - Defending world champion Sebastian Vettel topped both practice sessions at the Indian Grand Prix Friday as he bids for his fourth win in a row -- and a historic third straight drivers title.

The Red Bull driver, 25, who seized the championship lead at the last race in South Korea and is seeking to become Formula One's youngest triple champion, scorched a fastest lap of one minute and 26.221 seconds in the second session. He finished ahead of his Australian team-mate Mark Webber with Ferrari's Fernando Alonso, the long-time championship leader now supplanted by Vettel, third fastest.

Germany's Nico Rosberg was fourth in the leading Mercedes car ahead of Kimi Raikkonen of Lotus and the two McLarens of Britons Lewis Hamilton and Jenson Button. Nico Hulkenberg was eighth for Force India ahead of Frenchman Romain Grosjean in the second Lotus and Brazilian Bruno Senna for Williams.

On a bright, dry day with a temperature of 28 degrees Celsius, the conditions were near-perfect as Vettel continued his irresistible form in Asia by topping the first session from Button, and staying ahead of the pack in the second.

Wins in Singapore, Japan and South Korea have lifted Vettel to a narrow, six-point lead in the standings but with strong momentum and growing belief that the German can seal the title over the last four races.

Both Alonso and Hamilton, who will leave McLaren for Mercedes next year, also impressed with heavy fuel loads, but there is widespread sentiment that Red Bull are back in the groove that brought them title doubles in 2010 and 2011.