Heavy rain from Silverstone two weeks' ago seemed to follow MotoGP to Assen for Thursday morning's opening practice session for the Dutch TT.
The rain arrived in the opening minutes of the 45-minute session and soon soaked the track.
All 17 riders - including injured Tech 3 Yamaha team-mates Cal Crutchlow and Colin Edwards - took to the track in the grim conditions, throwing long spray trails from their rear tyres as they sliced through the standing water.
Marco Simoncelli typically showed no sign of shyness after his Silverstone crash as he set the fastest time of the session, the San Carlo Honda Gresini rider finishing 0.360sec ahead of fellow Italian Valentino Rossi.
It was a promising, if inconclusive, start for the newly announced 'Ducati Desmosedici GP11.1', which Rossi is riding for the first time this weekend.
Third fastest was world championship leader Casey Stoner (+0.491sec) with Repsol Honda team-mate Andrea Dovizioso one place behind the Australian (+0.604sec).
The first of the Yamaha's was reigning world champion Jorge Lorenzo in fifth (+0.959sec), with Crutchlow - who broke his collarbone at Silverstone - a brave sixth (+1.350sec).
The Englishman was inside the top ten throughout the session and had been as high as third.
Fellow rookie Karel Abraham was seventh for Cardion AB Ducati (+1.377sec) with Edwards eighth (+1.932sec) and Rossi's team-mate Nicky Hayden, who has a new chassis but not the 'new' bike, in ninth (+2.241sec).
Lorenzo's team-mate Ben Spies completed the top ten (+2.554sec).
With Dani Pedrosa absent for a third race in a row, following his collarbone injury at Le Mans last month, HRC has promoted Hiroshi Aoyama to the Repsol squad, with factory test rider Kousuke Akiyoshi filling in for Aoyama at Gresini.
Aoyama was twelfth (+4.096sec) this morning, with Akiyoshi 16th (+4.317sec).
This weekend's event marks the 81st Dutch TT. The first was in 1925 and it has taken place every year since, with the exception of 1940-1945 because of the Second World War.
The event - always held on the last Saturday in June - formed part of the original 1949 FIM Road Racing World Championships and has continued to host the Dutch round ever since. Assen is the only circuit to have remained on the calendar since 1949.
Factory Yamaha riders Lorenzo and Spies are both using a special white and red livery this weekend, to celebrate the 50th anniversary of Yamaha's involvement in grand prix racing.
Thursday practice (1):
17. de Puniet