Red Bull's Sebastian Vettel has remained the quickest driver in the final practice session for the Singapore Grand Prix.

The Championship leader was also quickest in P2, but was run close in the third practice session by Romain Grosjean of Lotus Renault.

Mercedes drivers Nico Rosberg and Lewis Hamilton were not far behind, but it was a disappointing drive for Fernando Alonso.

The Ferrari man was sixth fastest and with traffic towards the end of the run, it became difficult for anyone to go faster that Vettel.

Qualifying takes place later this afternoon.

Third practice full standings:

1. Sebastian Vettel (Red Bull)
2. Romain Grosjean (Lotus)
3. Nico Rosberg (Mercedes)
4. Mark Webber (Red Bull)
5. Lewis Hamilton (Mercedes)
6. Fernando Alonso (Ferrari)
7. Sergio Perez (McLaren)
8. Nico Hulkanberg (Sauber)
9. Jenson Button (McLaren
10. Felipe Massa (Ferrari)
11. Jean-Eric Vergne (Toro Rosso)
12. Kimi Raikkonen (Lotus)
13. Pastor Maldonado (Williams)
14. Daniel Ricciardo (Toro Rosso)
15. Valteri Bottas (Williams)
16. Paul Di Resta (Force India)
17. Esteban Gutierrez (Sauber)
18. Adrian Sutil (Force India)
19. Giedo van der Garde (Caterham)
20. Charles Pic (Caterham)
21. Jules Bianhi (Marussia)
22. Max Chilton (Marussia)