Aron Canet topped the opening day of Moto3 practice for the Dutch TT, after FP1 pacesetter Jorge Martin crashed heavily in the second session.
Martin led the way in the morning session at Assen with a 1:42.771s to lead the field by close to four tenths of a second.
The Gresini rider went top in the latter stages of FP1 with a 1:44.207s, which he improved to a 1:43.205s prior to his final effort of 1:42.771s.
Championship leader Marco Bezzecchi slotted into second on his Prustel GP machine ahead of fellow KTM rider John McPhee on the CIP bike. Canet and Catalunya race winner Enea Bastianini completed the top five.
Martin shot to the top of the standings early on at the start of the second session with a 1:43.488s, though this was quickly usurped by Bezzecchi, who posted a 1:43.324s.
Bezzecchi further improved to a 1:42.965s, which stood as the benchmark for much of FP2, with McPhee taking over top spot in the final minutes with a 1:42.832s.
The Scotsman's time at the head of the timesheets was short lived, however, as Canet guided his Estrella Galicia 0,0 Honda to a 1:42.677s to take over top spot in FP2 and on the combined times.
RBA's Grabriel Rodrigo jumped up to second in FP2 at the end, pipping McPhee, though both are shuffled back a spot on the combined times by virtue of Martin's 1:42.771s from FP1.
Martin's FP2 came to a crunching halt in the final minutes after suffering a highside exiting Turn 4. The Spaniard was stretchered off track, but was conscious and talking to the circuit medical staff.
Schedl GP's Philipp Oettl's 1:42.856s put him into fourth in FP2 and fifth overall ahead of Nicolo Bulega, whose return to form on his Sky Racing VR46 KTM continues after a strong Catalunya weekend.
Bezzecchi headed team-mate Jakub Kornfeil by two hundredths in seventh on the combined times, with Kaito Toba and Martin's Gresini stablemate Fabio Di Giannantonio completing the top 10.
