SINGAPORE (AP) Nico Rosberg set the fastest time in practice Friday for the Singapore Grand Prix, while Mercedes teammate and title rival Lewis Hamilton could manage only seventh after being hampered by a hydraulics failure.
Rosberg, who has won the past two races and trails Hamilton by only two points, recovered from a crash into a tire barrier in the first session at the Marina Bay street circuit.
In the night session - with greater grip and in conditions more representative of what they will face in Saturday's qualifying and Sunday's race - he was a quarter of a second faster than Ferrari's Kimi Raikkonen, with Red Bull's Max Verstappen a further tenth of a second back in third.
The presence of Mercedes, Ferrari, and Red Bull in close proximity at the top of the timesheets promises a hard-fought qualifying and race, living up to expectations that this grand prix was one in which the usually dominant Mercedes could be vulnerable.
The headline times promised a tight qualifying shootout, while the long-run times during Friday's sessions were also close, indicating an even contest Sunday.
Daniel Ricciardo was fourth fastest, only a couple of hundredths of a second behind teammate Verstappen despite the young Dutchman having the advantage of the exclusive use of the upgraded Renault engine while Ricciardo used the old version.
Ferrari's Sebastian Vettel was fifth and Nico Hulkenberg of Force India sixth ahead of Hamilton.
The Briton sat out the last third of the evening session due to low hydraulic fluid pressure, and there was not enough time to get it fixed and return him to the track.
Even before that, Hamilton was struggling on the ultra-soft tire, with which the fastest times were set, having twice run wide off the racing line.
''It doesn't look like anything serious,'' Hamilton said of the hydraulics issue. ''The guys are working on it and it should be fine for tomorrow, which is the main thing.
''Our pace looked OK today, definitely much better than last year so I'd say we're looking relatively strong.''
The two practice sessions represented a reversal of fortunes for the Mercedes rivals, as it was Rosberg who had the major problem in the early session. The German badly misjudged the tricky left-hand turn 18 and crashed nose first into the safety barrier before limping back to the pits with his front wing missing.
Barring unforeseen circumstances, Rosberg will start his 200th career grand prix here.
Toro Rosso's Carlos Sainz Jr. was eighth fastest and his teammate Daniil Kvyat 10th, separated by McLaren's Fernando Alonso.