Red Bull driver Sebastian Vettel set the fastest time in Friday's opening practice for the Indian Grand Prix, boosting his hopes of taking a fourth successive race win and extending his Formula One championship lead.
Vettel was three tenths of a second faster than McLaren's Jenson Button around the Buddh International Circuit, while his chief title rival Fernando Alonso of Ferrari was third fastest.
McLaren's Lewis Hamilton was fourth on the time sheets, ahead of Red Bull's Mark Webber, while Lotus' Kimi Raikkonen - the only other driver in title contention - was in 10th.
Sauber's Sergio Perez sat out the session with flu-like symptoms, but the team expected him to be fit to take part in the second practice later Friday. He was replaced by Mexican compatriot Esteban Gutierrez, who is widely expected to take the seat permanently next season when Perez moves to McLaren.
There was some sliding around a circuit made dirty and dusty by a year without racing, but no major incidents.
The Mercedes pair of Nico Rosberg and Michael Schumacher were sixth and eighth-fastest respectively, separated by Ferrari's Felipe Massa, while Toro Rosso's Daniel Ricciardo was ninth.
Vettel's string of three successive wins in the Asian swing of the season has seen him overtake Alonso in the drivers' championship standings, six points ahead of the Ferrari driver who has now gone half a dozen races without a win.
Ferrari is using new front and rear wings this race weekend, having supposedly cured problems in its wind tunnel development program.
Alonso is in turn, 42 points clear of third-placed Raikkonen with four races to go, indicating the season will boil down to a head-to-head contest between the Spaniard and Vettel.