Mercedes' expected 1-2 in Friday's second practice at the Hungaroring was blighted by a crash from Lewis Hamilton leaving Nico Rosberg alone at the top of the timesheet.
15 minutes into the session, and P1 at the time on the soft tyres, Hamilton lost it on the kerbs which pitched him into a spin and into the barriers at Turn 11.
The impact, which was side on, did not cause much damage to his W07 and Hamilton was able to slowly make his way back to the pits.
But despite that Mercedes revealed that the Brit's session was over. "Although he made it back to garage, car needs to be fully stripped and checked after impact with barrier," said the team.
The session also had to be red flagged for a few minutes as marshals repaired the Turn 11 barrier, which had been dented in the impact.
With the action back underway, Rosberg went quickest on the supersofts with a 1:20.435.
That put him 0.595s up on Daniel Ricciardo while Sebastian Vettel was third for Ferrari, and the only other driver to get within a second of Rosberg's P1 time.
Max Verstappen was fourth fastest, 1.335s off the pace, while Hamilton's time on the soft tyres was still good enough for fifth place ahead of Kimi Raikkonen, Fernando Alonso and Jenson Button.
Both Valtteri Bottas and Carlos Sainz ended the session under investigation; Bottas for failing to keep the correct side of a bollard coming into the pit lane and Sainz for crossing the pit entry line.
There were a few late incidents at Turn 2 as Kevin Magnussen spun and reported a puncture. Felipe Nasr was off in the gravel with a mechanical and Carlos Sainz spun seconds later – and all at Turn 2. Sainz's session ended shortly after in the Turn 1 gravel.
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