The F1 field is set to take a step into the unknown for the second successive race weekend after rain in Practice Two compounded the morning's diesel-spill delays on a frustrating opening day to the Russian GP.
Two weeks after Friday practice in Japan proved a washout, drivers completed limited representative mileage when heavy rain from the start of P2 essentially ended hopes that they could make up for time lost in P1.
Only eight drivers set timed laps during the course of the 90-minute session, all on the full wet tyres, with Williams' Felipe Massa fastest on a 2:00.458 - nearly 20 seconds slower than last year's dry pace.
The flip side of Friday's effective write-off is that extra significance has now been placed on Saturday morning's final practice session, when drivers will have just an hour to settle on a dry-weather set-up for qualifying and the race. The weekend weather forecast is for fairer conditions in the Black Sea resort of Sochi.
World championship rivals, and Mercedes team-mates, Lewis Hamilton and Nico Rosberg completed only installation laps mid-way through the session, while Ferrari's Kimi Raikkonen chose not to venture out at all.
Ferrari team-mate Sebastian Vettel did complete some timed laps in the wet, finishing second to Massa by two tenths of a second. Williams' Valtteri Bottas was third ahead of Toro Rosso's Max Verstappen and McLaren's Fernando Alonso, who was called into the pits late on with another technical problem on his car.
"The story of the first day of track action is there is no story," quipped Sky Sports F1's Ted Kravitz. However, the lack of on-track incident was in sharp contrast to the situation off the track in the Sochi paddock with Red Bull's search for a 2016 engine becoming increasingly precarious.
Friday's running itself was precarious at times due to a lack of grip, but Rosberg says it wasn't a completely wasted Friday for either him or Mercedes.
"Not a great day - especially for the fans who have come to watch us! I still went out there and did a few things, some starts and procedures, and pushed a little bit in the wet to get an idea," he told Sky Sports F1.
"We tried something on the rear wing, so we learned something on that. In the end I wanted to do a few more laps but in the end the car wasn't adequately set-up for the conditions so it was better to box."
Practice Two timesheet:
1. Felipe Massa, Williams, 2:00.458
2. Sebastian Vettel, Ferrari, 2:00.659
3. Valtteri Bottas, Williams, 2:00.688
4. Max Verstappen, Toro Rosso, 2:00.806
5. Fernando Alonso, McLaren, 2:01.077
6. Daniil Kvyat, Red Bull, 2:01.418
7. Carlos Sainz, Toro Rosso, 2:02.805
8. Jenson Button, McLaren, 2:02.845
9. Nico Rosberg, Mercedes, No time
10. Marcus Ericsson, Sauber, No time
11. Lewis Hamilton, Mercedes, No time
12. Sergio Perez, Force India, No time
13. Nico Hulkenberg, Force India, No time
14. Daniel Ricciardo, Red Bull, No time
15. Kimi Raikkonen, Ferrari, No time
16. Romain Grosjean, Lotus, No time
17. Felipe Nasr, Sauber, No time
18. Pastor Maldonado, Lotus, No time
19. Will Stevens, Manor, No time
20. Roberto Merhi, Manor, No time
Don't miss Sky Sports F1's live weekend-long coverage of the 2015 Russian Grand Prix. Our race-day show begins at 10.30am on Sunday, with lights out at 12 noon. Watch the Russian GP for £6.99 with NOW TV