Nico Rosberg has pipped his Mercedes teammate Lewis Hamilton to the fastest time in practice one of the Spanish Grand Prix at the Circuit de Catalunya.

The Mercedes duo dominated the timesheets in the early stages of the session, with Ferrari pair Sebastian Vettel and Kimi Raikkonen not far behind.

Fernando Alonso, who crashed at this circuit in February during pre-season testing, finished the practice unscathed and 15th fastest.

Susie Wolff took to the track, which warmed up as temperatures increased over the course of the morning, and clocked the 14th-quickest time for Williams, while Red Bull's Daniel Ricciardo was missing for the majority of the session.

Full standings:

1. Nico Rosberg (Mercedes)
2. Lewis Hamilton (Mercedes)
3. Sebastian Vettel (Ferrari)
4. Kimi Raikkonen (Ferrari)
5. Carlos Sainz Jr (Toro Rosso)
6. Max Verstappen (Toro Rosso)
7. Daniil Kvyat (Red Bull)
8. Felipe Nasr (Sauber)
9. Felipe Massa (Williams)
10. Nico Hulkenberg (Force India)
11.Daniel Ricciardo (Red Bull)
12. Raffaele Marciello (Sauber)
13. Jolyon Palmer (Lotus)
14. Susie Wolff (Williams)
15. Fernando Alonso (McLaren)
16. Jenson Button (McLaren)
17. Sergio Perez (Force India)
18. Pastor Maldonado (Lotus)
19. Will Stevens (Manor)
20. Roberto Merhi (Manor)