MELBOURNE, Australia (AP) Mercedes drivers dominated Friday's practice sessions for Formula One's season-opening Australian Grand Prix as expected, while other teams wrestled with mechanical problems, and even a legal dispute.
Nico Rosberg set the day's fastest time during the second practice session at Melbourne's Albert Park circuit, just a tenth of a second ahead of teammate and reigning world champion Lewis Hamilton, as the team lived up to expectations of continued dominance in 2015.
''To arrive here and have such good pace in the car for the second year in a row is an amazing feeling,'' Hamilton said, while acknowledging he was ''not 100 percent comfortable with the car'' on the softer tire.
Having such a large margin over rival teams meant Rosberg probably did not have to look beyond the team garage to know where the championship fight will be this season.
''It seems again that it's very close between Lewis and me, and he is a great driver, so I need to nail the setup every time to come out on top,'' Rosberg said. ''This year will be a big battle again against him, I'm sure.''
Ferrari drivers Sebastian Vettel and Kimi Raikkonen were the next fastest, but well behind Mercedes' pace. Third-placed Vettel - making his first official appearance for the team after leaving Red Bull - was seven-tenths of a second behind Rosberg.
Red Bull's Daniel Ricciardo, the local favorite, was forced to miss the second session after an engine replacement, which is a serious concern as new regulations restrict each car to four engines for the season before penalties kick in.
Williams driver Felipe Massa also missed the session due to a water leak, and Toro Rosso's 17-year-old rookie Max Verstappen barely participated in the second session due to a reported battery issue.
Such teething problems are common at the season-opening grand prix, and predictable for McLaren, which has struggled throughout preseason testing with its new Honda power unit. While Jenson Button was able to do some sustained running in the second session - a sobering 1.4 seconds off the top pace - Kevin Magnussen crashed into a tire wall early. Magnussen is standing in for Fernando Alonso, who will miss the season-opening race due to injury.
Williams driver Valtteri Bottas was fifth-fastest in the second session, ahead of Red Bull's Daniil Kvyat. Toro Rosso rookie Carlos Sainz Jr., Lotus drivers Pastor Maldonado and Romain Grosjean, and Force India's Nico Hulkenberg rounded out the top 10.
Sauber skipped the opening session due to an ongoing legal dispute with driver Giedo van der Garde, but enough progress was made in that dispute to allow Marcus Ericsson and Felipe Nasr to participate in the second session.
Van der Garde maintains he was promised a seat with Sauber for the 2015 season, but the team dumped him in favor of Ericsson and Nasr in November. The Supreme Court in the Australian state of Victoria ruled Wednesday that van der Garde should be able to race in Melbourne, and rejected a Sauber appeal on Thursday. They were in court again on Friday with van der Garde's lawyers pursuing a contempt of court action, arguing the team had not done enough to comply with the previous rulings. That hearing is scheduled to continue on Saturday.
The Manor team, having been taken out of administration by new ownership just two weeks ago, took no part as it scrambles to make its car ready. Principal among the concerns is re-loading the complex software systems into its computers. The software was wiped from the computers to enable them to be sold as part of the administration process. The computers were not sold, but all the material has to be re-entered.
Team principal Graeme Lowdon was unsure if the team will be able to participate in Saturday's qualifying, and therefore Sunday's race.
''I don't know, but what I can guarantee you is in terms of commitment and rate of problem solving, we will be absolutely flat out,'' Lowdon said.
Even if the team does manage to get going for qualifying on Saturday, its unlikely to be within seven per cent of the pole sitter's time, which is the standard required to take part in the race.