Mercedes driver Nico Rosberg continued to look impressive ahead of this weekend's Monaco Grand Prix by topping the standings for the second practice session.

The German driver was fastest during first practice earlier in the day, and he looked in dominant mood in the second, finishing ahead of teammate Lewis Hamilton.

The Ferrari duo of Fernando Alonso and Felipe Massa finished in third and fourth respectively, while Red Bull's Mark Webber ended the session in fifth position.

Lotus Renault driver Kimi Raikkonen was sixth quickest, with McLaren's Jenson Button in eighth.

Championship leader Sebastian Vettel was more than a second off the pace in ninth.

Second practice full standings:

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