On a productive morning for teams only pacesetter Perez failed to pass a half century of laps.
Alfa Romeo’s Kimi Raikkonen led the way on the mileage charts as he completed a mammoth 91 laps in the Ferrari-powered C41.
Perez’s benchmark left him 0.299s clear of Leclerc’s early placeholder while McLaren’s Lando Norris finished third, and Pierre Gasly fourth, the only other drivers to classify within a second of Perez.
Alpine’s Esteban Ocon took fifth, in front of Haas rookie Mick Schumacher, who gained valuable mileage ahead of his grand prix debut.
Valtteri Bottas was seventh for Mercedes while George Russell took eighth as he got his first experience behind the wheel of Williams’ FW43B.
Raikkonen and Aston Martin’s Lance Stroll, who concentrated on longer runs, rounded out the 10 entrants.
The final session of pre-season testing will begin at 15:00 local time.