Ferrari lay down a marker ahead of São Paulo Grand Prix qualifying with Carlos Sainz finishing top of the timesheets in practice.
The Spaniard set a benchmark of a 1:11.732 to finish 0.108secs faster than teammate Charles Leclerc at Interlagos, with George Russell third for Mercedes.
But the picture is muddied by the lack of Soft tyre running for so much of the field, with Red Bull, Mercedes and McLaren failing to set a lap on the red side-walled compound.
Result Free practice 1 - Brazilian
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With just an hour of running afforded to drivers before qualifying and a threat of rain hanging over Interlagos for the afternoon, the track was instantly a hive of activity with all 20 competitors running the Hard tyres.
Max Verstappen was instantly fastest on the white side-walled compound and by the end of the initial runs found himself just 0.025s faster than teammate Perez, with George Russell also within a tenth for Mercedes.
In a largely undramatic session, Verstappen complained of a 'flexing seat' while Esteban Ocon warned his Alpine team that a screw had found its way to the surface of one of his tyres, though the Frenchman escaped a puncture.
Aston Martin's Fernando Alonso was not so lucky, however, with his team detecting a rear-left puncture for the two-time champion on his first set of Hards.
Daniel Ricciardo was consigned to the AlphaTauri garage for around a quarter of the session having picked up floor damage, though quick repairs allowed the Australian to return to the track.
Lando Norris and Nico Hulkenberg then bizarrely made contact at Junção with 25 minutes left on the clock with the McLaren on a hot lap and Haas dawdling, with the stewards placing the incident under investigation. Both drivers continued undamaged, though the German reported a loss of power after running over kerbs in the final 10 minutes.
Further issues arose when Williams was forced to abandon Logan Sargeant's qualifying simulation as the American three-wheeled around corners - his front wheels lifting from the ground. Work quickly began on the left rear of the FW45 before he returned for the final seven minutes.
With times unrepresentative given the varying programmes being completed from team to team, the final results show a mixed order.
Sainz and Leclerc led the way having both used Softs, with Russell's effort on Mediums good enough for third.
Hulkenberg was within two-tenths of the fastest time with his Soft-tyre run, ahead of Alex Albon's Williams - also on the Softs.
Lance Stroll put his Aston Martin ahead of Alpine's Pierre Gasly for sixth and seventh - both drivers on Mediums - whilst the final three in the top 10 all ran Softs. Zhou Guanyu finishing ahead of Sargeant and Haas' Kevin Magnussen for Alfa Romeo.
Lewis Hamilton was only 12th after running Hards and Mediums, whilst both Red Bulls ran just the Hards - Verstappen ending the session 16th and Perez 18th.