Following a two-and-a-half hour delay to repair the loose water valve covers that damaged cars and caused FP1 to be cancelled, second practice eventually got underway at 2.30am local time (10.30am UK).
FP2 was extended by half an hour to become a 90-minute session and give teams extra track time after opening practice was abandoned after just nine minutes.
And it was Leclerc who topped the timesheets, 0.517s clear of teammate Carlos Sainz, who has been hit with a 10-place grid penalty after Ferrari were forced to make changes to his car after it was damaged beyond repair as a result of him striking a loose water valve in FP1.
Aston Martin’s Fernando Alonso finished third-quickest, 0.528s adrift of Leclerc’s benchmark.
Sergio Perez was the fastest Red Bull driver in fourth, ahead of Alfa Romeo’s Valtteri Bottas, who was an eye-catching fifth, ahead of world champion and Perez’s teammate Max Verstappen.
Nico Hulkenberg put his Haas seventh, ahead of Aston Martin’s Lance Stroll and Lewis Hamilton’s Mercedes, while Alex Albon rounded out the top-10 in his Williams.
Second practice took place with no fans in attendance after police were seen clearing the grandstands before the session started for “logistical considerations”, according to the organisers.