At the first practice session in Monaco, McLaren were expected to set the pace. Instead, it was Kimi Raikkonen's Ferrari that topped the time-sheets on Thursday.
Raikkonen and Ferrari teammate Felipe Massa had always maintained that Ferrari would be very competitive in Monaco, at least a good match for McLaren, who usually dominate around this track.
And so it proved as Raikkonen clocked a fastest lap of one minute 15.948 seconds through the twisting street circuit of Monte Carlo, just 0.268 seconds ahead of Lewis Hamilton.
Hamilton's McLaren team-mate Heikki Kovalainen was third fastest, with Ferrari's Felipe Massa just behind.
The Williams of Nico Rosberg also came on strong as he recorded the fifth fastest time, with BMW's Robert Kubica behind him. BMW again look slightly off the pace against McClaren and Ferrari, with Nick Hieldfeld languishing down in 14th place.
Two-time winner of Monaco Fernando Alonso placed seventh in his Renault, followed by Rubens Barrichello's Honda in eighth, Mark Webber in the Red Bull ninth and the Force India of Giancarlo Fisichella rounding off the top 10.
David Coulthard stopped his Red Bull after only three laps, as he had to pull over after his Red Bull had a small fire. He ended up last with no time set.
Nick Heidfeld also had to withdraw after 13 laps, while Jarno Trulli buckled his wheel after his Toyota clipped a barrier coming out of the tunnel.
First free practice times for the Monaco Grand Prix:
1. Kimi Raikkonen (Finland) Ferrari 1min 15.948 seconds
2. Lewis Hamilton (Britain) McLaren-Mercedes 1:16.216
3. Heikki Kovalainen (Finland) McLaren-Mercedes 1:16.248
4. Felipe Massa (Brazil) Ferrari 1:16.292
5. Nico Rosberg (Germany) Williams - Toyota 1:16.653
6. Robert Kubica (Poland) BMW Sauber 1:16.834
7. Fernando Alonso (Spain) Renault 1:17.498
8. Rubens Barrichello (Brazil) Honda 1:17.511
9. Mark Webber (Australia) RedBull - Renault 1:17.798
10. Giancarlo Fisichella (Italy) Force India - Ferrari 1:17.835
11. Timo Glock (Germany) Toyota 1:17.942
12. Jenson Button (Britain) Honda 1:18.153
13. Sebastien Bourdais (France) Toro Rosso - Ferrari 1:18.245
14. Nick Heidfeld (Germany) BMW Sauber 1:18.263
15. Kazuki Nakajima (Japan) Williams - Toyota 1:18.274
16. Jarno Trulli (Italy) Toyota 1:18.360
17. Adrian Sutil (Germany) Force India - Ferrari 1:18.360
18. Nelson Piquet (Brazil) Renault 1:18.955
19. Sebastian Vettel (Germany) Toro Rosso - Ferrari 1:19.176
20. David Coulthard (Britain) RedBull - Renault no time