Formula One: Sebastian Vettel scorches to lap record in first Indian Grand Prix practice

Sebastian Vettel began his quest to seal a fourth successive Formula One title by scorching a new lap record in first free practice at the Indian Grand Prix on Friday. (Racecentre)

The 26-year-old, enjoying a 90-point lead over his nearest challenger Fernando Alonso, only needs to finish in the top five in his Red Bull on Sunday to seal the title.

Vettel showed ominous intent by lapping at 1min 26.68secs, surpassing his own record of 1:27.24 set at the inaugural race at the Buddh International Circuit in 2011.

Vettel's Red Bull team-mate Mark Webber, who leaves F1 at the end of the season, was only narrowly slower as he came in second at 1:26.87.

Nico Rosberg of Mercedes was third at 1:26.89, followed by Romain Grosjean and Lewis Hamilton -- all under the previous lap record.

Vettel, who has won the last five races this season, romped home easily in India in 2011 and 2012 and is strong favourite to triumph again on Sunday.

However, anything higher than a sixth-place finish and Vettel will join compatriot Michael Schumacher and Juan Manuel Fangio of Argentina as the only drivers to win four consecutive F1 titles.

The only way Vettel can be denied is if he fails to score a point in the remaining four races -- provided Ferrari's Alonso wins at least three of them and finishes second in the other.

Victories in the last four races in India, Abu Dhabi, America and Brazil would also put Vettel level with Schumacher's 2004 record of 13 wins in a single season.