Lewis Hamilton set the pace in first free practice for the Bahrain Grand Prix on Friday.
The World Champion was comfortably fastest for most of the session and even a late charge from BMW drivers Nick Heidfeld and Robert Kubica on the super-soft tires was not enough to topple the Briton.
After the now seemingly obligatory 20-minute silence following the installation laps on Friday morning, Sebastien Bourdais was the first to lap the circuit properly. But very quickly his time was eclipsed by Nico Rosberg who put in a sequence of laps that culminated in a 1m34.363s best. That was good enough to keep the German at the top of the times until just beyond the halfway mark when Hamilton moved ahead.
The McLaren man appeared to benefit from the latest modifications to the MP4-24 to produce a 1m34.189s lap time.
An interesting characteristic of the Bahrain circuit though was that it took drivers several laps to get the best out of the Bridgestone medium slicks – and so it was that Hamilton then improved again to go 0.716sec faster than the Williams.
His 1m33.647s lap was not bettered by anyone for the rest of the session, but Rosberg would succumb to the soft-rubbered BMWs late in the session. The Williams driver might have improved himself but for yellow flags at Turn 8 when Sebastian Buemi's Toro Rosso stopped on the exit of Turn 8 late-on.
Behind the top four, was World Championship leader Jenson Button, who struggled early in the session with an upshift problem in his gearbox.
Heikki Kovalainen was sixth for McLaren ahead of the second Brawn of Rubens Barrichello.
Felipe Massa and Mark Webber were next up, while Ferrari's Kimi Raikkonen was lucky to complete the session in tenth. The Finn was one of several drivers to have a moment, but his involved a lurid slide that saw him just miss the barriers at Turn 2 right at the start of practice.
Turn 10 saw more than its fair share of action as well, with Kovalainen, Fernando Alonso, Buemi, Fisichella, Heidfeld just some of the drivers to run wide at the tricky tight left-hander.
Pos Driver Team Time Laps
1. Hamilton McLaren-Mercedes (B) 1:33.647 + 19
2. Heidfeld BMW Sauber (B) 1:33.907 + 0.260 17
3. Kubica BMW Sauber (B) 1:33.938 + 0.291 17
4. Rosberg Williams-Toyota (B) 1:34.227 + 0.580 24
5. Button Brawn GP-Mercedes (B) 1:34.434 + 0.787 15
6. Kovalainen McLaren-Mercedes (B) 1:34.502 + 0.855 24
7. Barrichello Brawn GP-Mercedes (B) 1:34.531 + 0.884 18
8. Massa Ferrari (B) 1:34.589 + 0.942 17
9. Webber Red Bull-Renault (B) 1:34.827 + 1.180 21
10. Raikkonen Ferrari (B) 1:34.827 + 1.180 19
11. Nakajima Williams-Toyota (B) 1:34.880 + 1.233 24
12. Vettel Red Bull-Renault (B) 1:34.938 + 1.291 21
13. Piquet Renault (B) 1:34.974 + 1.327 21
14. Sutil Force India-Mercedes (B) 1:35.021 + 1.374 18
15. Trulli Toyota (B) 1:35.036 + 1.389 22
16. Fisichella Force India-Mercedes (B) 1:35.042 + 1.395 16
17. Glock Toyota (B) 1:35.333 + 1.686 20
18. Alonso Renault (B) 1:35.348 + 1.701 24
19. Bourdais Toro Rosso-Ferrari (B) 1:35.353 + 1.706 22
20. Buemi Toro Rosso-Ferrari (B) 1:35.369 + 1.722 15
All timing unofficial