Mercedes driver Nico Rosberg has set the pace in the first practice for the Monaco Grand Prix.
The 27-year-old managed to pip his teammate Lewis Hamilton by finishing three tenths of a second ahead of the former McLaren star with a time of 1:16.195.
There were three drivers between the teammates in the practice standings, as Ferrari's Fernando Alonso clocked the second-fastest time of 1:16.282, while Lotus Renault driver Romain Grosjean finished third quickest.
Midway through the session drama occurred when Ferrari's Felipe Massa made a late decision to enter the pit lane, causing Marussia's Max Chilton to hit the brakes to avoid colliding with his competitor.
Meanwhile, 2012 champion Sebastian Vettel finished the session in his Red Bull car 10th in the standings with a time of 1:17.380.
First practice full standings:
1. Nico Rosberg (Mercedes)
2. Fernando Alonso (Ferrari)
3. Romain Grosjean (Lotus Renault)
4. Felipe Massa (Ferrari)
5. Lewis Hamilton (Mercedes)
6. Pastor Maldonado (Williams)
7. Mark Webber (Red Bull)
8. Jenson Button (McLaren)
9. Sergio Perez (McLaren)
10. Sebastian Vettel (Red Bull)
11. Kimi Raikkonen (Lotus Renault)
12. Paul di Resta (Force India)
13. Adrian Sutil (Force India)
14. Nico Hulkenberg (Sauber)
15. Jean-Eric Vergne (STR Ferrari)
16. Esteban Gutierrez (Sauber)
17. Valtteri Bottas (Williams)
18. Daniel Ricciardo (STR Ferrari)
19. Giedo van der Garde (Caterham)
20. Charles Pic (Caterham)
21. Jules Bianchi (Marussia)
22. Max Chilton (Marussia)
