Jack Miller led the way in a soaking wet opening practice at the TT Circuit Assen ahead of Suzuki’s Joan Mir.
Rain continued to hit the Dutch venue hard throughout the 45-minute session, meaning that track action was relatively light throughout the middling stages, times falling frequently as riders continued to gather in confidence.
Miller utilised his customary strong wet weather form to lead the way early on with a 1:44.523s, though the heavy precipitation ended up causing several areas of standing water to manifest around the circuit – causing the majority of the riders to wait until the conditions improved.
The rain started to ease as the session entered its climactic stages though and times soon began to plummet once again as on less than four different riders took turns to head the timing sheets, though it would be Miller’s 1:42.589s in the closing moments that would keep him on top as the chequered flag brought the session to an end.
Mir ended up grabbing second on his GSX-RR at the death ahead of Pol Espargaro, the Honda man having led the way at several points as he looked comfortable with his RC213-V in the sodden conditions.
Alex Marquez ended up fourth on his LCR Honda ahead of Aprilia’s Aleix Espargaro, with KTM’s Miguel Oliveira managing the sixth best effort.
Alex Rins made his return having missed the bulk of the German Grand Prix weekend as a result of his fractured left wrist and took seventh on the sister Suzuki ahead of Pramac Ducati duo Johann Zarco and Jorge Martin, with Maverick Vinales rounding off the top ten.
Francesco Bagnaia led the way towards the start of the final runs, though the Italian was eventually shuffled back to 11th by the end.
Yamaha duo Franco Morbidelli and Fabio Quartararo looked speedy in the opening minutes as they diced over the top spot between themselves and Miller, though they failed to improve much on their earlier gambits towards the conclusion of the test and slipped back to 15th and 17th respectively.
Several riders fell victim to Turn 1 during the session as the white line on the entry to the bend was incredibly slippery, Ducati riders Marco Bezzecchi and Enea Bastianini both suffering fast falls at the corner while the likes of Mir and Vinales took turns in running through the gravel as they out-braked themselves while entering the turn.
