Rubens Barrichello was fastest in the first practice session around the tight and twisty Monte Carlo circuit.
The Brawn GP star was followed by Ferrari s Felipe Massa with last year s winner, Lewis Hamilton, in third.
There was also drama for Red Bull, as Sebastian Vettel suffered a costly engine failure midway through the session.
Pos Driver Team Time Laps 1. Barrichello Brawn-Mercedes (B) 1:17.189 25 2. Massa Ferrari (B) 1:17.499 + 0.310 31 3. Hamilton McLaren-Mercedes (B) 1:17.578 + 0.389 25 4. Kovalainen McLaren-Mercedes (B) 1:17.686 + 0.497 29 5. Raikkonen Ferrari (B) 1:17.839 + 0.650 30 6. Nakajima Williams-Toyota (B) 1:18.000 + 0.811 29 7. Rosberg Williams-Toyota (B) 1:18.024 + 0.835 27 8. Button Brawn-Mercedes (B) 1:18.080 + 0.891 27 9. Alonso Renault (B) 1:18.283 + 1.094 30 10. Webber Red Bull-Renault (B) 1:18.348 + 1.159 22 11. Buemi Toro Rosso-Ferrari (B) 1:18.695 + 1.506 36 12. Piquet Renault (B) 1:19.204 + 2.015 36 13. Vettel Red Bull-Renault (B) 1:19.233 + 2.044 16 14. Bourdais Toro Rosso-Ferrari (B) 1:19.255 + 2.066 30 15. Fisichella Force India-Mercedes (B) 1:19.534 + 2.345 27 16. Kubica BMW-Sauber (B) 1:19.560 + 2.371 20 17. Heidfeld BMW-Sauber (B) 1:19.579 + 2.390 22 18. Sutil Force India-Mercedes (B) 1:19.600 + 2.411 23 19. Glock Toyota (B) 1:19.698 + 2.509 23 20. Trulli Toyota (B) 1:19.831 + 2.642 28
