Red Bull's Max Verstappen clocked in fastest in first practice for the Azerbaijan Grand Prix, the Dutchman edging Ferrari's Charles Leclerc by just 0.043s.
Carlos Sainz confirmed the Scuderia's street circuit form as he completed the top three, while Mercedes enjoyed a slow start to its Baku weekend with Lewis Hamilton and Valtteri Bottas concluding their morning session P7 and P10 respectively.
After Monaco, F1 takes to the streets of Baku, but save for a few tight and twisty corners there is little in common between the two urban venues, although Red Bull is determined to pick up where it left off in Monte Carlo.
F2 practice raised the curtain on Friday morning, allowing for a handy clean-up of the dusty circuit, but Baku's tarmac was still fairly 'green' when drivers were given the green light for FP1.
And there was no hanging about as 17 out of the field's 20 drivers sprung into action at the outset, with Verstappen, Bottas and Hamilton joining the action later than their colleagues.
Aero checks were also in order early on, with several cars sporting flow-vis paint jobs or test rigs, including McLaren's chargers which reverted to their papaya livery.
Charles Leclerc positioned himself at the top of the time sheet as he set the session's first benchmark time, but the Ferrari driver was quickly overhauled by Hamilton.
But as he pressed on, the Briton, running on the soft tyre, lowered the fastest lap to a 1m43.893 that comfortably cleared Verstappen and AlphaTauri's Pierre Gasly.
Halfway through the session, Hamilton remained on top, with Leclerc and Norris in tow, but Daniel Ricciardo then suddenly leapfrogged the group to go fastest by 0.161s.
Norris was then on course for a dynamite lap, but the McLaren charger threw it away with a 180-degree spin at turn 16, contrary to Leclerc and Sainz who promptly dispatched Ricciardo at the top by half a second!
In the meantime, Hamilton indulged in a rare mistake when he locked up and was caught out at Turn 15, but fortunately with no other consequence than a set of burned up rubber.
Down the road, Verstappen expressed his frustration over the radio with the inattentive Nikita Mazepin after his flyer was ruined by the Haas rookie.
But the Dutchman, now free of traffic, charged on and duly snatched P1 with a 1m43.184s that edged Leclerc by 0.043s.
A series of lock-ups in Turns 15 and 16 prompted several local yellow flags that disrupted the final minutes of the session and prevented any improvements.
Verstappen thus remained on top from Leclerc and Sainz, with Ferrari emulating early on its Monaco form. Perez, Ricciardo and Gasly rounded off the top six while a few botched laps left Hamilton down in P7, in front of Norris, Alpine's Fernando Alonso and Bottas.
Both Alfa Romeo and Aston Martin pairs concluded the morning in the second half as did Yuki Tsunoda and Esteban Ocon, while the Williams and Haas drivers brought up the rear.
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