Home rider Michael van der Mark set the fastest overall time in Friday's three World Superbike practice sessions as Jonathan Rea topped both FP1 and FP2.
Jonathan Rea began his quest for a 12th Assen WSBK win by topping the opening 40-minute practice of the weekend, the championship leader guiding his Kawasaki to a 1m35.662s in the closing minutes.
Home hero van der Mark shadowed Rea with a 1m35.931, while Xavi Fores ended the morning as the top Ducati rider on his Barni-run Panigale in third spot, ahead of Tom Sykes.
The session was briefly red-flagged after a light fall for Aprilia's Lorenzo Savadori at Turn 8, though the Milwaukee team was able to get the Italian back out with over half of the session remaining to go 12th fastest.
Rea carried on his session-topping form in FP2, missing out on the existing outright lap record by just over a tenth of a second with a 1m33.630s, with teammate Sykes being only 0.078s slower in second.
Melandri – who was testing various aerodynamic updates in a bid to cure his stability issues - was third quickest in FP2, while his factory Ducati stablemate Chaz Davies was a somewhat more low-key 9th in the second session, having ended FP1 fifth.
Improvements were few and far between for much of the third session, though a frantic closing segment saw Rinaldi and van der Mark trade fastest laps, with the latter edging two tenths clear of the Italian rookie with a 1m35.156s.
Melandri also beat Rinaldi with his final attempt, while Rea ended the day fourth on the combined times as he failed to improve on his FP2 best.
Lowes completed the top five on the second Yamaha, jumping ahead of Sykes, who also didn't improve on his FP2 time on his Kawasaki.
Fores was shuffled to seventh at the end of the day ahead of Davies, Savadori and MV Agusta's Jordi Torres, who clung onto the final spot in Superpole 2 despite sitting in his garage for the closing stages of FP3.
The Ten Kate Honda team come into the Assen round a man down after Leon Camier was forced to sit out following his crash in Aragon last weekend.
The team's sole representative for their home round Jake Gagne was an encouraging 13th at the end of FP1, but suffered a monster highside crash at Turn 12 midway through FP2.
Passed fit prior to FP3, he opted to sit out the session.
Combined Friday times
|1||Michael van der Mark||Yamaha||57||1'35.156|
|3||Michael Ruben Rinaldi||Ducati||41||1'35.518||0.362|
|10||Jordi Torres||MV Agusta||42||1'36.002||0.846|