Although a dry line quickly emerged during the 20-minute session, no riders used slick tyre, with the medium-compound wet tire proving the rubber of choice for most riders.
Vinales became the first rider to breach the two-minute barrier with a little over a minute to go when he posted a 1m59.524s, knocking KTM’s Mika Kallio off the top spot.
Crutchlow then grabbed the top spot with a 1m59.400s aboard the LCR Honda, before Vinales responded with a final effort of 1m59.111s to go 0.289s clear.
Read So:
Joan Mir was third for Suzuki, 0.403s off the pace, ahead of another rookie, Francesco Bagnaia on the Pramac Ducati, while Valentino Rossi was the only other rider to set a time in the 1m59s in fifth on the second works Yamaha.
Kallio was sixth ahead of Crutchlow’s teammate Takaaki Nakagami and Alex Rins’ Suzuki.
Front-row starter Fabio Quartararo ended up down in 17th, more than four seconds off the pace, while poleman Marc Marquez was one of four riders not to set a timed lap.