Spa-Francorchamps, Belgium - Lewis Hamilton bounced back to the top of the time sheets for Mercedes ahead of Kimi Raikkonen of Ferrari in Friday's second free practice ahead of this weekend's Belgian Grand Prix.
The three-time world champion, who is 14 points adrift of Sebastian Vettel of Ferrari in this year’s title race ahead of his 200th Grand Prix, was second behind the Finn in the opening session.
Hamilton clocked a best lap in one minute and 44.753 seconds to finish 0.262 seconds ahead of Raikkonen, who marked the confirmation of his Ferrari contract for 2018 with a speedy showing round the spectacular Spa-Francorchamps circuit.
The session began in bright and dry conditions, but finished in teeming rain as the micro-climate of the forests of the Belgian Ardennes delivered a capricious dose of its changeable weather.
Hamilton’s Mercedes team-mate Valtteri Bottas was third quickest ahead of Dutchman Max Verstappen of Red Bull and championship leader Vettel.
Australian Daniel Ricciardo, who was 1.32 seconds off the leading pace, was sixth in the second Red Bull ahead of Nico Hulkenberg of Renault, Esteban Ocon of Force India, Carlos Sainz of Toro Rosso and Briton Jolyon Palmer in the second Renault.
Felipe Massa of Williams took no part in the session after crashing and damaging his car on his opening lap of the opening session on Friday morning.
Raikkonen dominates first practice
Ferrari's Kimi Raikkonen lapped fastest in first practice but even then Lewis Hamilton looked every bit the man to beat.
A four times winner at Spa, and with a contract extension for 2018 announced earlier in the week, Raikkonen lapped the longest track on the calendar with a best time of one minute 45.502 seconds in the closing minutes.
The 37-year-old Finn's time was set on the quickest ultra-soft tyres, however, while Hamilton - preparing for his 200th race start - was second fastest and only 0.053 slower on the soft compound.
Hamilton was 0.092 faster than Ferrari's world championship leader Sebastian Vettel, with the German third on the timesheets and also setting his time on the quickest but least durable tyre.
Vettel leads Hamilton by 14 points with nine rounds remaining.
Red Bull's Dutch teenager Max Verstappen, Belgian-born and attracting a huge travelling support of orange-capped fans, was fourth fastest - also on ultra-softs - with Australian team-mate Daniel Ricciardo fifth.
Hamilton's team-mate Valtteri Bottas, who bumped into the tyre barrier after going off across the gravel and damaged his front wing, was sixth fastest.
The session was halted after 15 minutes when Brazilian Felipe Massa, who missed the previous race in Hungary after feeling dizzy in practice, crashed heavily into the tyre barrier at turn seven out of Les Combes.
He was taken to the medical centre for checks, before returning to the pitlane, with his team facing a long job rebuilding the car. The session resumed after a 10 minute stoppage.
Williams said the chassis would have to be changed and the team still hoped to get the car back out on track for some of the day's second session, even if that looked like being optimistic.
Fernando Alonso suffered a lack of power in his McLaren, but still ended up 13th fastest. Belgian team-mate Stoffel Vandoorne, who will start his home race last on Sunday thanks to a 35 place penalty due to a power unit change, was 10th.
FIRST FREE PRACTICE:
1. Kimi Raikkonen (Finland) Ferrari 1:45.502
2. Lewis Hamilton (Britain) Mercedes 1:45.555
3. Sebastian Vettel (Germany) Ferrari 1:45.647
4. Max Verstappen (Netherlands) Red Bull - TAG Heuer 1:46.302
5. Daniel Ricciardo (Australia) Red Bull - TAG Heuer 1:46.352
6. Valtteri Bottas (Finland) Mercedes 1:46.424
7. Carlos Sainz Jr (Spain) Toro Rosso - Renault 1:47.446
8. Esteban Ocon (France) Force India - Mercedes 1:47.670
9. Daniil Kvyat (Russia) Toro Rosso - Renault 1:47.851
10. Stoffel Vandoorne (Belgium) McLaren 1:47.865
11. Jolyon Palmer (Britain) Renault 1:47.930
12. Nico Huelkenberg (Germany) Renault 1:48.037
13. Fernando Alonso (Spain) McLaren 1:48.252
14. Sergio Perez (Mexico) Force India - Mercedes 1:48.452
15. Lance Stroll (Canada) Williams-Mercedes 1:48.541
16. Kevin Magnussen (Denmark) Haas - Ferrari 1:48.615
17. Romain Grosjean (France) Haas - Ferrari 1:48.626
18. Marcus Ericsson (Sweden) Sauber - Ferrari 1:50.160
19. Pascal Wehrlein (Germany) Sauber - Ferrari 1:51.263
20. Felipe Massa (Brazil) Williams-Mercedes
SECOND FREE PRACTICE
1. Lewis Hamilton (Britain) Mercedes 1:44.753
2. Kimi Raikkonen (Finland) Ferrari 1:45.015
3. Valtteri Bottas (Finland) Mercedes 1:45.180
4. Max Verstappen (Netherlands) Red Bull - TAG Heuer 1:45.225
5. Sebastian Vettel (Germany) Ferrari 1:45.235
6. Daniel Ricciardo (Australia) Red Bull - TAG Heuer 1:46.072
7. Nico Huelkenberg (Germany) Renault 1:46.441
8. Esteban Ocon (France) Force India - Mercedes 1:46.473
9. Carlos Sainz Jr (Spain) Toro Rosso - Renault 1:46.561
10. Jolyon Palmer (Britain) Renault 1:46.670
11. Fernando Alonso (Spain) McLaren 1:46.743
12. Sergio Perez (Mexico) Force India - Mercedes 1:46.984
13. Romain Grosjean (France) Haas - Ferrari 1:47.285
14. Stoffel Vandoorne (Belgium) McLaren 1:47.303
15. Daniil Kvyat (Russia) Toro Rosso - Renault 1:47.450
16. Kevin Magnussen (Denmark) Haas - Ferrari 1:47.556
17. Lance Stroll (Canada) Williams-Mercedes 1:47.861
18. Marcus Ericsson (Sweden) Sauber - Ferrari 1:49.214
19. Pascal Wehrlein (Germany) Sauber - Ferrari 1:49.725
20. Felipe Massa (Brazil) Williams-Mercedes