Suzuka - Nico Rosberg gave his wounded team mate Lewis Hamilton plenty to think about by topping the timesheets in both practice sessions Friday for the 2016 Japanese Grand Prix.
Rosberg, who has a 23-point championship lead over Hamilton with five races left this year, pipped the triple world champion by two tenths in the morning sunshine and just 0.072sec under cloudy skies in the afternoon.
Rosberg struck an early psychological blow as he goes for his fourth win in five races, despite complaining of "monster understeer" in the early jousting between the two fierce Mercedes rivals.
As it happened: Japanese GP - 2nd practice
Hamilton, by contrast, has had a tumultuous few days after a blown engine robbed the Briton of victory last weekend.
After controversially hinting that his Malaysia heartbreak was a result of sabotage from within the Mercedes garage, Hamilton barked over the radio that his car was "very low on power" in the morning session.
He improved after lunch but was still unable to surpass the pace of Rosberg, who is in the form of his life.
The Formula 1 championship leader survived a scare when he emerged from the garage with smoke pouring from his exhaust.
No harm was done, however, as Rosberg set the quickest lap of 1min 32.250sec.
Hamilton followed him out and was quicker in sector one but slower than his team-mate in sector two to clock 1:32.322.
Kimi Raikkonen was third fastest in the second session, just three tenths off Rosberg's pace with Red Bull's Max Verstappen splitting the Ferraris in fourth, a shade quicker than Sebastian Vettel.
Australian Daniel Ricciardo, who profited from Hamilton's misfortune to lead a Red Bull one-two in Malaysia, missed out on his qualifying practice after the virtual safety car was activated but went back out for a long run.
Mexican Esteban Gutierrez climbed out of his Haas after informing his pit crew simply: "Okay, something broke."
Earlier, Haas team-mate Romain Grosjean smashed his car into the crash barriers but avoided turning the air blue after recently promising to stop being "an a##hole in the car".
Instead, he stuck to the facts as he backed out of the gravel, reporting: "The brake doesn't brake."
In the afternoon, Grosjean was still minding his p's and q's, politely telling his team: "I cannot see the pitboard."
There was drama for Alonso, running Honda's latest engine at Suzuka, as the Spaniard skidded off at the devilish 'Spoon' curve and mangled his rear wing.
The focus now shifts to Saturday's qualifying 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 problem and the Briton is reverting to the engine he used in Singapore this weekend. Rosberg is using the same power unit he ran in Malaysia.
2016 Japanese GP:
Second practice
1. Nico Rosberg (GER) Mercedes 1min32.250
2. Lewis Hamilton (GBR) Mercedes 1min32.322
3. Kimi Raikkonen (FIN) Ferrari 1min32.573
4. Max Verstappen (NED) Red Bull 1min33.061
5. Sebastian Vettel (GER) Ferrari 1min33.103
6. Sergio Perez (MEX) Force India 1min33.570
7. Nico Hulkenberg (GER) Force India 1min33.873
8. Fernando Alonso (ESP) McLaren 1min33.985
9. Valtteri Bottas (FIN) Williams 1min34.028
10. Carlos Sainz Jr (ESP) Toro Rosso 1min34.086
11. Felipe Massa (BRA) Williams 1min34.127
12. Daniel Ricciardo (AUS) Red Bull 1min34.150
13. Romain Grosjean (FRA) Haas 1min34.241
14. Daniil Kvyat (RUS) Toro Rosso 1min34.305
15. Kevin Magnussen (DEN) Renault 1min34.339
16. Jenson Button (GBR) McLaren 1min34.398
17. Esteban Gutierrez (MEX) Haas 1min34.643
18. Jolyon Palmer (GBR) Renault 1min34.760
19. Felipe Nasr (BRA) Sauber 1min34.824
20. Pascal Wehrlein (GER) Manor 1min35.292
21. Esteban Ocon (FRA) Manor 1min35.400
22. Marcus Ericsson (SWE) Sauber 1min36.318
1. Nico Rosberg (GER) Mercedes 1min32.431
2. Lewis Hamilton (GBR) Mercedes 1min32.646
3. Sebastian Vettel (GER) Ferrari 1min33.525
4. Kimi Raikkonen (FIN) Ferrari 1min33.817
5. Daniel Ricciardo (AUS) Red Bull 1min34.112
6. Max Verstappen (NED) Red Bull 1min34.379
7. Nico Hlkenberg (GER) Force India 1min34.530
8. Sergio Perez (MEX) Force India 1min34.767
9. Fernando Alonso (ESP) McLaren 1min35.003
10. Valtteri Bottas (FIN) Williams 1min35.381
11. Daniil Kvyat (RUS) Toro Rosso 1min35.446
12. Carlos Sainz Jr (ESP) Toro Rosso 1min35.672
13. Jenson Button (GBR) McLaren 1min35.677
14. Romain Grosjean (FRA) Haas 1min35.688
15. Felipe Nasr (BRA) Sauber 1min35.967
16. Felipe Massa (BRA) Williams 1min36.169
17. Esteban Gutierrez (MEX) Haas 1min36.219
18. Marcus Ericsson (SWE) Sauber 1min36.294
19. Kevin Magnussen (DEN) Renault 1min36.822
20. Esteban Ocon (FRA) Manor 1min37.797
21. Pascal Wehrlein (GER) Manor 1min37.966
22. Jolyon Palmer (GBR) Renault 1min37.992