Ferrari topped the timesheet with Kimi Raikkonen in the third practice session of the Belgian Grand Prix, while Daniel Ricciardo was second-fastest in his Red Bull at Spa today.
Mercedes sealed a one-two in the first practice session with Nico Rosberg and Lewis Hamilton on Friday, while Max Verstappen and Ricciardo dominated the second.
Hamilton, who is likely to start at the back of the grid following a 30-place penalty, attempted a late surge in the final minute of today's session on super-soft tyres, but he could only record the fifth-fastest lap.
Rosberg was seven tenths of a second slower than Raikkonen as he clocked the sixth-quickest time, while Verstappen ended up back in the garage in the early stages of the session due to problems with his Red Bull.
Third practice standings:
1. Kimi Raikkonen (Ferrari)
2. Daniel Ricciardo (Red Bull)
3. Sebastian Vettel (Ferrari)
4. Valtteri Bottas (Williams)
5. Lewis Hamilton (Mercedes)
6. Nico Hulkenburg (Force India)
7. Nico Rosberg (Mercedes)
8. Felipe Massa (Williams)
9. Sergio Perez (Force India)
10. Romain Grosjean (Haas)
11. Fernando Alonso (McLaren)
12. Esteban Gutierrez (Haas)
13. Jenson Button (McLaren)
14. Kevin Magnussen (Renault)
15. Pascal Wehrlein (Manor)
16. Daniil Kvyat (Toro Roso)
17. Carlos Sainz Jr (Toro Rosso)
18. Jolyon Palmer (Renault)
19. Felipe Nasr (Sauber)
20. Esteban Ocon (Manor)
21. Marcus Ericsson (Sauber)
22. Max Verstappen (Red Bull)