Max Verstappen leads Red Bull one-two in first Saudi practice
Aston Martin's Fernando Alonso, third in the March 5th opener in Bahrain behind Verstappen and Perez, was again the best of the rest.
Last year's winner Verstappen, who delayed his arrival in the kingdom as he recovered from the bug, got straight down to work with a fastest lap of one minute 29.617 seconds.
Perez was 0.483 slower with double world champion Alonso 0.698 off Verstappen's pace and Canadian teammate Lance Stroll, still recovering from breaking both wrists and a big toe in a pre-season cycling accident, fourth.
The Mercedes pair of George Russell and Lewis Hamilton were fifth and sixth and Ferrari's Carlos Sainz was the seventh quickest.
Ferrari's Charles Leclerc, who will have a 10 place penalty on the grid for Sunday's race after a change of electronic control unit, was 11th.