The Ferrari debutant clocked his best time of a 1m18.247s, just one-tenth shy of his team-mate’s best time on the first day of testing.
It leaves the Scuderia continuing to assert their dominance in testing as the team look to win their first championship since 2008.
Ferrari power continues to impress
Ferrari customer teams also continued their good form, with Haas driver Kevin Magnussen ending the day third and Antonio Giovinazzi fifth in his Alfa Romeo.
Both drivers, however, were over nine tenths slower than the pace set by Leclerc, who completed a total of 157 laps during the day.
Times set by Ferrari powered teams so far are encouraging signs for the Italian engine, although it is likely that reigning world champions Mercedes and the new Honda-powered Red Bull are still yet to show their hand.
Mercedes drivers Valtteri Bottas and Lewis Hamilton ended the day in sixth and tenth place, whilst Pierre Gasly went seventh fastest following a crash in the afternoon.
The new Red Bull driver brought out the red flag after spinning on the entry into turn 12 and hitting the wall, although the damage looked minor following the incident.
Rookie drivers show good form
Toro Rosso debutant Alexander Albon also had an incident during the morning, spinning into the gravel trap.
However, the rookie put his Toro Rosso in an impressive fourth place, whilst new McLaren signing Lando Norris ended the session second.
The Brit continued McLaren’s impressive run in testing, with Carlos Sainz also finishing second for the Woking based team on the first day of testing.
Renault remain down the order
Daniel Ricciardo, who suffered a rear wing failure during the session, could only place his Renault ninth whilst team-mate Nico Hulkenberg went eight fastest.
It is likely improvement is yet to come, however, as the French team target to challenge the top three with their new RS19.
New Racing Point driver Lance Stroll ended the day 11th fastest, with Haas test driver Pietro Fittipaldi ending the session in last place.
Williams remained absent from testing although are set to give their new FW42 some track time on Wednesday.