IN THE WET: Ferrari's Kimi Raikkonen drives on a soaked track during the 2015 Japanese GP first session. Image: AFP / Kazuhiro Nogi
SUZUKA, Japan, Sept 25 - A rain soaked first Japanese Grand Prix practice on Friday provided no immediate answers to questions about how Formula One world champions Mercedes would fare after their mysterious Singapore slump last weekend.
Championship leader Lewis Hamilton was fifth fastest for Mercedes but the Briton spent most of the time in the garage and completed only six laps, while title rival team mate Nico Rosberg was third.
Eight of the 20 drivers failed to set a time on a slippery track with steady rain and cars throwing up plumes of spray when they did go out.
Spanish rookie Carlos Sainz was fastest for Toro Rosso, despite problems with aquaplaning, with a best time of one minute 49.434 seconds.
It was the first time in his 14 race career that Sainz had led a session.
Red Bull's Russian Daniil Kvyat was next on the time sheets but half a second slower while Hamilton's best lap was 1.288 seconds off the pace but meaningless given the conditions.
Ferrari's Sebastian Vettel, winner from pole position in Singapore for his third victory of the season, was fourth quickest but on intermediate tyres rather than the full wets used by Hamilton.
Brazilian Felipe Massa, in a Williams, and Ferrari's Kimi Raikkonen both had spins.
Vettel's speed in Singapore raised questions about whether Mercedes were suffering circuit-specific problems or whether Ferrari and Red Bull had managed to rein in their hitherto dominant rival.
Suzuka, a fast track with challenging corners, should be much more to Mercedes' liking but both Hamilton and Rosberg had hoped for more reassurance than they were able to get from Friday's session.
Financially-struggling Lotus, whose freight was delivered only on Thursday, remained locked out of their paddock hospitality due to payment problems.
Lotus reserve driver Jolyon Palmer, replacing Romain Grosjean for the session, managed only an installation lap and later Tweeted a picture of himself 'enjoying' the team's VIP hospitality - sitting on the floor of the garage with a packet of crisps.
2015 Japanese Grand Prix 1st practice results
1. Carlos Sainz Jr (Spain) Toro Rosso - Renault 1min49.434
2. Daniil Kvyat (Russia) RedBull - Renault 1min49.938
3. Nico Rosberg (Germany) Mercedes 1min50.077
4. Sebastian Vettel (Germany) Ferrari 1min50.519
5. Lewis Hamilton (Britain) Mercedes 1min50.722
6. Max Verstappen (Netherlands) Toro Rosso - Renault 1min50.940
7. Kimi Raikkonen (Finland) Ferrari 1min51.212
8. Felipe Massa (Brazil) Williams-Mercedes 1min52.288
9. Marcus Ericsson (Sweden) Sauber - Ferrari 1min53.820
10. Valtteri Bottas (Finland) Williams-Mercedes 1min53.964
11. Felipe Nasr (Brazil) Sauber - Ferrari 1min54.013
12. Jenson Button (Britain) McLaren 1min55.678
13. Daniel Ricciardo (Australia) RedBull - Renault
14. Nico Hulkenberg (Germany) Force India - Mercedes
15. Sergio Perez (Mexico) Force India - Mercedes
16. Fernando Alonso (Spain) McLaren
17. Pastor Maldonado (Venezuela) Lotus - Mercedes
18. Jolyon Palmer (Britain) Lotus - Mercedes
19. Will Stevens (Britain) Marussia - Ferrari
20. Alexander Rossi (U.S.) Marussia - Ferrari