Casey Stoner has taken his sixth pole position in a row after a commanding wet weather performance during qualifying at the Czech Republic Grand Prix, on a day when two riders (technically) failed to qualify due to the appalling conditions.

Following two dry Friday practice sessions, in which Valentino Rossi and Stoner led one session each, intermittent rain fell on the Brno circuit throughout Saturday - with a heavy shower arriving just before the start of the MotoGP qualifying hour

Stoner, looking to rebound from a bitter defeat inflicted by Rossi at a thrilling US GP, had been a comfortable half-second clear of the field on Saturday morning - despite a limited number of laps - and remained in a class of his own during the afternoon.

Stoner was 3.2secs in front after just ten minutes, although Rossi had eroded the Australian's advantage down to 1.189secs as the midway stage approached - at which point the rain intensified, ending the battle for pole.

Sunday's front row will be completed by Kawasaki's John Hopkins, returning from injury this weekend, after the Anglo-American edged out former Rizla Suzuki team-mate and wet weather expert Chris Vermeulen by just 0.043secs.

Rookie Alex de Angelis, a promising fifth in the dry, continued his excellent weekend with a repeat of that position in the wet - making him the top satellite rider on a day when team-mate Shinya Nakano, making his debut on a factory RC212V this weekend, took eighth.

Rain specialist Anthony West bucked the trend by delivering his best lap of the afternoon at the very end of the session, propelling the under-pressure Kawasaki rider up to an encouraging sixth on the grid.

The rain did nothing to dampen Bridgestone's dominance of the resurfaced Brno circuit, the Japanese brand conquering the top six qualifying positions and - as in free practice - boasted nine riders inside the top ten. The exception was Michelin-shod Randy de Puniet who qualified 2.878secs behind Stoner, in seventh, for Honda LCR.

Rizla Suzuki's Loris Capirossi, third on Friday, speared off track in the early part of the session and was forced to ditch his GSV-R just before an air fence. The Italian recovered to claim ninth on the grid, with Sylvain Guintoli tenth for Alice Ducati.

Stoner's troubled team-mate Marco Melandri was an improved eleventh in the slick conditions, but was ahead of only one other Bridgestone rider - Alice's Toni Elias in 13th.

Injured world championship contender Dani Pedrosa was the second best Michelin rider, in a distant twelfth for Repsol Honda, while fellow Michelin competitors Andrea Dovizioso (JiR Honda), Colin Edwards (Tech 3 Yamaha), James Toseland (Tech 3 Yamaha) and Jorge Lorenzo (Fiat Yamaha) were left to fill the tail end of the grid, from 14th to 17th.

Toseland, who fell on corner entry just after the halfway stage, and fellow class rookie Lorenzo technically failed to qualify for Sunday's race - lapping 11.6secs and 12.0secs from Stoner - but will doubtless be allowed to take part due to the exceptional nature of the track conditions.

Opinion is divided as to what weather to expect for the race.

Qualifying:

1. Stoner
2. Rossi
3. Hopkins
4. Vermeulen
5. de Angelis
6. West
7. de Puniet
8. Nakano
9. Capirossi
10. Guintoli
11. Melandri
12. Pedrosa
13. Elias
14. Dovizioso
15. Edwards
16. Toseland
17. Lorenzo