Ferrari's Michael Schumacher, chasing his sixth win in a row, fired an early warning today with the fastest time in first free practice for Sunday's Monaco Grand Prix.
The six times world champion, also hoping for a record-equalling sixth Monaco victory, threaded his red race car through the tight city streets in one minute 16.502 seconds.
Schumacher has already equalled the best start to a Formula One season, Briton Nigel Mansell's five in a row in 1992, and has his sights on Italian Alberto Ascari's record run of nine successive wins for Ferrari in 1952-53.
The Honda-powered BARs were the German's closest rivals but the gap was still more than three quarters of a second.
Japan's Takuma Sato was second quickest in 1:17.279 and Briton Jenson Button the third fastest in 1:17.339 on a hot, cloudy morning in the Mediterranean principality.
McLaren's David Coulthard, a two times Monaco winner who was gloomy about the struggling team's prospects on Wednesday, produced the fifth quickest time.
Brazilian Rubens Barrichello, in the second Ferrari, was more than two seconds slower than Schumacher and ended the session with the 12th best time.
Germany's Ralf Schumacher, on pole in Monaco last year, failed to set a time while Williams team mate and 2003 winner Juan Pablo Montoya was ninth on the timesheets.
The three Jordan cars of Giorgio Pantano, test driver Timo Glock and Nick Heidfeld finished 18th, 19th and 21st respectively.
The session was interrupted for six minutes when Jaguar's Australian Mark Webber hurriedly pulled over between the new chicane and Tabac corner, gesticulating to marshals to extinguish an engine fire.
When the marshals appeared to react slowly, Webber seized an extinguisher himself. The car then had to be lifted off the track by crane before the session could continue.
Today's first free practice times
1. Michael Schumacher (Germany) Ferrari one minute 16.502 seconds
2. Takuma Sato (Japan) BAR 1:17.279
3. Jenson Button (Britain) BAR 1:17.339
*4. Ricardo Zonta (Brazil) Toyota 1:17.426
5. David Coulthard (Britain) McLaren 1:17.524
6. Fernando Alonso (Spain) Renault 1:17.686
*7. Anthony Davidson (Britain) BAR 1:17.791
8. Jarno Trulli (Italy) Renault 1:17.856
9. Juan Pablo Montoya (Colombia) Williams 1:17.937
10. Kimi Raikkonen (Finland) McLaren 1:17.952
11. Giancarlo Fisichella (Italy) Sauber 1:18.336
12. Rubens Barrichello (Brazil) Ferrari 1:18.621
13. Cristiano de Matta (Brazil) Toyota 1:18.889
14. Olivier Panis (France) Toyota 1:19.218
15. Mark Webber (Australia) Jaguar 1:19.261
16. Felipe Massa (Brazil) Sauber 1:19.335
17. Christian Klien (Austria) Jaguar 1:19.487
18. Giorgio Pantano (Italy) Jordan 1:20.528
*19. Timo Glock (Germany) Jordan 1:20.534
*20. Bjorn Wirdheim (Sweden) Jaguar 1:20.680
21. Nick Heidfeld (Germany) Jordan 1:21.141
22. Gianmaria Bruni (Italy) Minardi 1:21.201
23. Zsolt Baumgartner (Hungary) Minardi 1:22.203
*24. Bas Leinders (Belgium) Minardi 1:23.361
25. Ralf Schumacher (Germany) Williams
no time *denotes test drivers who will not race.