SUZUKA (AFP) - Nico Rosberg kept the pressure on wounded team-mate Lewis Hamilton on Friday by clocking the fastest time in the first free practice for this weekend's Formula One Japanese Grand Prix.
The German, who has a 23-point championship lead over Hamilton with five races left this season, pipped the Formula One world champion by 0.215 second as the two Mercedes topped the timesheets in the Suzuka sunshine.
Rosberg struck an early psychological blow as he goes for his fourth win in five races, despite complaining of "monster understeer" during the early jousting, recording a best lap of 1min 32.431sec.
Hamilton, by contrast, has had a tumultuous few days after a blown engine robbed the triple world champion of victory last weekend.
The Briton, who had hinted that his Malaysian heartbreak was a result of sabotage from within the Mercedes garage, barked over the radio that his car was "very low on power" in Friday's morning session.
Ferrari's Sebastian Vettel was third quickest, just over a second off Rosberg's pace, with team-mate Kimi Raikkonen fourth.
The Red Bulls of Daniel Ricciardo and Max Verstappen were next after their stunning one-two finish in Malaysia.
There was drama for McLaren's Fernando Alonso, running Honda's latest engine at the Japanese manufacturer's home race, as the Spaniard skidded off at the devilish "Spoon" curve and mangled his rear wing.
That prompted McLaren mechanics to ask politely: "Fernando, I see you've gone off, are you able to get back to the pits?"
Romain Grosjean also smashed his Haas into the crash barriers but avoided turning the air blue after recently promising to stop being "an asshole in the car".
Instead, the Frenchman stuck to the facts as he reversed out of the gravel, reporting: "The brake doesn't brake."
All eyes will be on Rosberg and Hamilton in Friday afternoon's second session as Hamilton looks to bounce back from a nightmare week and complete a hat-trick of Suzuka victories.
Mercedes blamed Hamilton's third engine failure of the year on a bearing failure and the Briton will revert to the engine he used in Singapore this weekend.
Rosberg will use the same power unit he ran in Malaysia, but Mercedes have put safeguards in place to avoid more technical mishaps in Japan by introducing "conservative" engine specifications.