MELBOURNE, Australia (AP) -- Formula One's three-time reigning world champion Sebastian Vettel signaled he is the man to beat again in 2013 by setting the fastest time in both practice sessions Friday for the season-opening Australian Grand Prix.
Vettel and Red Bull teammate Mark Webber set the two fastest times around the Albert Park circuit, immediately dashing the hopes of rivals who thought they'd caught up during the offseason.
Mercedes' Nico Rosberg was third quickest but suffered what an apparent gearbox failure late in the second session, shortly after new teammate Lewis Hamilton went off the track into a tire wall. The late problems put a tarnish on an otherwise promising afternoon for the team, which confirmed impressions from preseason testing that it would be pushing for podiums and even wins in the early stages of the season.
Lotus' Kimi Raikkonen and Romain Grosjean were fourth and fifth. The Ferrari pair Fernando Alonso and Felipe Massa were sixth and eighth - separated by Hamilton - while Force India's Adrian Sutil and Sauber's Nico Hulkenberg rounded out the top 10.
McLaren's Jenson Button, who has won three of the past four Australian races, was down the timesheets in 11th place, indicating the team still has some problems with its new design, which is more innovative than the conservative evolutions of rival teams. Button was 2.4 seconds off Vettel's time, while his new teammate Sergio Perez was a further quarter of a second back.
Much interest in the first official day of the 2013 season was centered on how the tires would perform, as the higher-degradation compounds raised the ire of just about all teams in preseason testing. They lasted better than expected, with most drivers managing more than two dozen laps on the medium tire and a dozen or more on the super softs.
Friday provided what may be the best chance of the weekend for teams to test their settings, as rain is forecast for Saturday and cool conditions for race day Sunday.
The street circuit was still slippery and dusty, but develops grip over the course of the weekend as rubber is laid down. Vettel's best time Friday was almost a full second off last year's pole position time, in cars of very similar specifications.
The practice sessions also gave the best indication yet of the early pecking order among the teams after the mysteries of preseason testing.
The order of best times Friday was: Red Bull, Mercedes, Lotus, Ferrari, Force India, Sauber, McLaren, Toro Rosso, Williams, Marussia and Caterham.