The predicted rain finally arrived in Monaco in time for the third and final free practice session ahead of qualifying, and produced a surprise pacesetter in the shape of Spyker's Adrian Sutil.

While the German will be the first to admit that his position was the result of the treacherous conditions, it was also due to a solid lap at the right time on a slowly drying track.

Already damp in places, the surface was thoroughly soaked by the time the session was a quarter old, giving the teams a tricky choice between preserving their equipment and finding a decent set-up should qualifying continue in the same vein. In the end, everyone ventured out to get a feel for the conditions, although the final timesheet reflected the unpredictable nature of the session.

The two Toyotas were among those to brave the worst of the elements, while Honda also took a turn at the head of the times while others deliberated, but the hour came down a frantic final few minutes as all 22 drivers attempted to set better times.

In the end, it was Sutil who got his timing just right, clocking 1min 36.312secs as he joined the train circulating at the end. And it was not simply a case of the young German being the last man out on track before the chequer fell, as several others followed him across the line after setting less optimal laps. In the end, Sutil enjoyed a tenth's advantage over second placed Kimi Raikkonen, with former F3 Euroseries team-mate Lewis Hamilton claiming third spot despite a couple of moments.

Giancarlo Fisichella had been at the head of the times when Sutil improved on the benchmark, the Italian eventually having to settle for fourth spot, one place ahead of Scott Speed, who also made the most of the slowly improving conditions to post a result hitherto out of the reach of Toro Rosso.

World champion Fernando Alonso was seventh fastest after languishing down the order during the heaviest of the rain, but the Spaniard was still better off than Felipe Massa, who failed to post a time in the best of the conditions and had to make do with twelfth spot.

Between the two, Heikki Kovalainen, Nico Rosberg, Jenson Button, Rubens Barrichello and Mark Webber gave the top half of the order a varied appearance, while Super Aguri claimed 13th and 14th spots, just ahead of the second Red Bull car of David Coulthard, which only moved off the bottom of the timesheets in the closing moments. The Scot still managed to lap faster than the two BMW Saubers, which suffered their worst session of the season in 16th and 18th, split by Alex Wurz, who was among those to spin in the tricky conditions.