Felipe Massa waited right to the end of a damp first practice session for the Canadian Grand Prix to go quickest in Montreal.
The Ferrari driver's laptime of 1:17.553 was good enough to fend off several last-ditch attempts from rivals as the timesheet resembled a fruit machine in the final moments of the 90 minutes.
In the end, it was BMW's Robert Kubica who got closest to the Brazilian's time, eclipsing Heikki Kovalainen and Nick Heidfeld, both of whom had in turn usurped Kimi Raikkonen from second place moments before.
But it was a question of being out on track at the right time as Jenson Button discovered when he dropped from fourth to last in just eight minutes.
The track was declared wet at the start of the session and predictably, only the Force India drivers ventured out initially, Giancarlo Fisichella having the measure of teammate Adrian Sutil when the track was at its most treacherous.
But at halfway, with a dry line emerging, the Toyotas of Jarno Trulli and Timo Glock took control of the session. And they stayed in charge when drivers began switching to dry tyres just after the 60-minute mark.
After that, Glock, who stayed top for a considerable amount of time, was a sitting duck, as first Raikkonen, then Nico Rosberg dispensed laptimes under the 1:20 mark.
From then, times cascaded as the timesheets scrolled almost permanently.
In the end, the world champion dropped to fifth ahead of Lewis Hamilton, who waited until the last seven minutes of the session before coming out to play.
Mark Webber set a time good enough for third when he was on track, but eventually dropped to seventh ahead of Red Bull teammate David Coulthard. Kazuki Nakajima and Fernando Alonso completed the top ten.
Rosberg, having twice topped the order, ended the session 11th.
Unsurprisingly, several drivers ran off the track, including Button, Trulli, Alonso, and Nelsinho Piquet, but no one made contact with the barriers.
Pos Driver Team Time Laps 1. Massa Ferrari (B) 1:17.553 14 2. Kubica BMW Sauber (B) 1:17.809 + 0.256 12 3. Kovalainen McLaren-Mercedes (B) 1:18.133 + 0.580 10 4. Heidfeld BMW Sauber (B) 1:18.182 + 0.629 13 5. Raikkonen Ferrari (B) 1:18.292 + 0.739 12 6. Hamilton McLaren-Mercedes (B) 1:18.303 + 0.750 8 7. Webber Red Bull-Renault (B) 1:18.712 + 1.159 11 8. Coulthard Red Bull-Renault (B) 1:18.809 + 1.256 12 9. Nakajima Williams-Toyota (B) 1:18.971 + 1.418 24 10. Alonso Renault (B) 1:19.005 + 1.452 13 11. Rosberg Williams-Toyota (B) 1:19.093 + 1.540 20 12. Vettel Toro Rosso-Ferrari (B) 1:19.228 + 1.675 21 13. Glock Toyota (B) 1:19.346 + 1.793 28 14. Trulli Toyota (B) 1:19.568 + 2.015 31 15. Fisichella Force India-Ferrari (B) 1:19.815 + 2.262 16 16. Sutil Force India-Ferrari (B) 1:19.888 + 2.335 15 17. Piquet Renault (B) 1:20.091 + 2.538 23 18. Barrichello Honda (B) 1:20.173 + 2.620 17 19. Bourdais Toro Rosso-Ferrari (B) 1:20.541 + 2.988 16 20. Button Honda (B) 1:21.542 + 3.989 17 All timing unofficial