Pramac Ducati's Jack Miller set the pace in this morning's first free practice at a wet Valencia, opening a near half-second gap over Franco Morbidelli with HRC test rider Stefan Bradl in third place.
But it was disaster for world championship challenger Fabio Quartararo whose wet-weather setup on the Petronas Yamaha is so bad he was stone last, 2.7s off the pace and 1.2s slower than Garrett Gerloff who has never seen Valencia, an M1 or Michelin tyres before.
Miller set a 1'42.063 on his eighth lap of 14, using the soft Michelin wets, which was 0.467s ahead of Morbidelli on the Petronas M1. Bradl was only 0.036s further back on Marc Marquez' RC213V.
Johann Zarco was again the fastest Ducati, setting a 1'42.639 with Alex Marquez fifth putting in a 1'42.654 before a crash.
Danilo Petrucci put his works Ducati into sixth with a lap 0.637 off the pace which was enough to keep Pol Espargaro's KTM in seventh with Miguel Oliveira in eighth.
Andrea Dovizioso finished ninth with Maverick Vinales in tenth. The Spaniard put in 19 laps despite saying yesterday that he would have to limit his track time due to a lack of engines.
Taka Nakagami, Aleix Espargaro, Aleix Rins, Pecco Bagnaia and Brad Binder completed the top 15 with Garrett Gerloff an impressive 16th and only 1.6s off the pace.
