Lewis Hamilton edged Mercedes team-mate Valtteri Bottas by 0.069s at the top of the timesheet in the opening practice session ahead of the Formula 1 French Grand Prix.
The Paul Ricard circuit started the weekend low on grip, as several drivers suffered significant tyre graining early in the session on the red-marked soft tyre.
Mercedes fared better than most, with Bottas posting the benchmark pace in the first 40 minutes of the 90-minute practice.
Fitting a brand new soft rubber, Bottas and Hamilton exchanged top spot after the mid-session pause with the championship leader recording a 1m32.738s best lap to end up on top.
Bottas was fastest in sector two but lost time in the technical final sector, ending up 0.069s adrift at the flag.
Charles Leclerc was third for Ferrari despite complaining about tyre graining early on. He was 0.373s slower than Hamilton.
His team-mate Sebastian Vettel struggled to fifth place. Prior to posting his session-best effort, Vettel radioed to the pitwall that “something doesn’t feel right on the front.”
Failing to break into the top 10 on his first lap of his final run, Vettel’s improvement to fifth place was delivered on the second timed effort.
Both Red Bull’s suffered spins during the session, with Max Verstappen looping his car at the chicane of Turns 8 and 9 before Pierre Gasly lost control over the Turn 4 apex kerb.
Both were spared by the large Paul Ricard run-off areas and managed to continue, ending the session in fourth and sixth respectively.
McLaren was comfortably best of the rest in first practice, with Lando Norris briefly occupying top spot on the timesheet at the mid-point in the session.
He finished seventh, 1.3 seconds off the pace while team-mate Carlos Sainz Jr was eighth.
Daniel Ricciardo was ninth for Renault, nearly half a second behind the lead McLaren, while Toro Rosso’s Alexander Albon rounded out the top 10.
Albon’s team-mate Daniil Kvyat, who enters the weekend guaranteed to start at the back of the grid on account of an out-of-allowance engine change, spun his car at the tight Turn 5 en route to 14th.
Both Racing Point drivers recorded their best times of the session on the medium tyre, with Sergio Perez ending up 11th and Lance Stroll in 13th, sandwiching Renault’s Nico Hulkenberg.
Williams reserve driver and Formula 2 championship leader Nicholas Latifi completed another FP1 session, this time replacing George Russell.
Latifi was 18th, narrowly edging team-mate Robert Kubica while both Williams drivers finished ahead of Romain Grosjean, whose session was compromised by a water leak.