Red Bull driver and Championship leader Sebastian Vettel has recorded the quickest lap in the second practice session of the Singapore Grand Prix at Marina Bay.

Vettel's teammate Mark Webber, who is leaving Formula 1 at the end of the season, clocked the second-fastest time, while Mercedes pair Nico Rosberg and Lewis Hamilton finished third and fourth in the list respectively.

Problems occurred for both Webber and Williams driver Pastor Maldonado on the penultimate corner of the track, with both hitting the wall and sending up sparks, but they were able to continue with their laps.

Maldonado had another crash later in the session by skidding into a barrier to break the front wing of his car, causing him to return to the pits.

Lotus driver Romain Grosjean could only muster 18 laps, which is less than half of the laps his competitors completed, due to reported hydraulics problems with his car.

Second practice full standings:

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