Monaco Grand Prix winner Sergio Perez extended his run of form into Friday's first practice in Baku where the Mexican led the opening practice session for the Azerbaijan Grand Prix.
The in-form Perez clocked with a 0.127s advantage over Ferrari's Charles Leclerc while Max Verstappen was third, 0.334s behind his teammate.
Carlos Sainz, Fernando Alonso and Lewis Hamilton rounded off the top six, but the Alpine and Mercedes driver were over a second behind the session's pace setter.
F1 teams kicked off in Baku the first round of a double-header that will take everyone to Montreal next week, which will provide little to turn things around and even lesser time to manage any major damages that could occur in Azerbaijan.
And Baku's track takes no prisoners when it comes to those who step over the line on the challenging layout.
While a street circuit, the venue has little in common with Monaco, save for its narrow and twisty section, and teams run with a lot less downforce around the track's 20-corner, 6.003km layout.
On the tyre front, Pirelli has supplied to teams the three softest compounds - C3,C4 and C5 - in its range
A flood of cars took to the track at the outset amid warm and sunny conditions.
After the usual routine involving installation and flo-viz laps, the field got going, with Verstappen setting the first benchmark time.
Just eight minutes into the session, Haas' Mick Schumacher went down an escape road, his VF-22 left stranded with water pouring from its side. The incident triggered a short Virtual Safety Car period as the Haas was evacuated.
Verstappen, running on the medium tyre, continued to press on, followed by Leclerc and Perez, but the Mexican leapfrogged the Ferrari driver to get within 0.735s of his Red Bull teammate while Leclerc was 1.189s behind Verstappen and just ahead of Alonso.
Still pushing, but now on the soft tyre as were his front-running rivals, Perez went one better and dispatched Verstappen with a 1m45.476s that edged the latter by an impressive 0.334s.
Behind the Red Bull pair, Sainz slotted in third ahead of Leclerc and Lewis Hamilton, but the Mercedes driver was a massive 1.490s adrift from Perez.
With 12 minutes left on the clock, Leclerc, running on a clear track, split the two bulls but an early assessment appeared to indicate that Ferrari's F1-75 is outpaced by the former's RB18 around Baku, thanks in part to a strong straight-line speed.
As the session headed towards its conclusion, the only change among the top five was a late hot lap by Alonso that pushed the Spaniard up to fifth and knocked Hamilton down to P6.
Meanwhile Verstappen gave his team a small scare in the dying seconds of the session due to a full but harmless spin at Turn 15.
AlphaTauri's Yuki Tsunoda enjoyed a productive opening session, clocking in sixth ahead of George Russell, his teammate Pierre Gasly and Alpine's Esteban Ocon.
Lando Norris was the leading driver in the McLaren camp in P11, the Briton heading the second part of the field from Lance Stroll, Kevin Magnussen and Sebastian Vettel while a subdued performance from Alfa Valtteri Bottas left the Finn 15th.
There was little improvement in the Williams camp with Alex Albon and Nicholas Latifi once again among the laggards. Finally, with just three laps under his belt, Schumacher unsurprisingly bookended the group in P20.
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