Nico Rosberg moved to the front during second practice for the Singapore Grand Prix on Friday, whilst Mercedes team-mate and championship leader Lewis Hamilton had a shortened session after problems hit his W07.
Rosberg's 1m44.152s put him over two-tenths clear of Ferrari's Kimi Raikkonen in second and a further tenth ahead of Max Verstappen's Red Bull in third.
Daniel Ricciardo and Sebastian Vettel were fourth and fifth, whilst Hamilton could only manage seventh, behind Force India's Nico Hulkenberg, as a hydrualic leak saw him garage bound for the final 30 minutes.
The Briton had been the early pacesetter before the issue struck.
Ricciardo too had problems of his own, though they were self-inflicted as the Australian clipped the wall at Turn 11, spinning, before continuing.
Two others also clipped the wall and escaped damage. Hulkenberg and Fernando Alonso, ninth. Alonso later came to a halt during the final minutes of the session.
Meanwhile Romain Grosjean had a heavy impact with the wall at the final corner, damaging the rear of his Haas. He completed just 12 laps during the session.
