Double Formula One champion Verstappen picked up where he left off in winning the Bahrain season-opener, lapping the Jeddah Corniche circuit with a best time of one minute 29.603 seconds on the fastest soft tyres in the evening session.
Last year's winner in Jeddah had lapped in 1:29.617 in practice one, when Mexican team mate Sergio Perez was second fastest and Alonso third.
Alonso, also a double champion and third in the March 5th opener behind Verstappen and Perez, was again in the mix throughout the day.
Verstappen had delayed his arrival in the kingdom as he recovered but he got straight up to speed, with the only drama being a close shave with the wall at the final corner in practice two.
Perez was 0.483 slower than Verstappen in session one and Alonso 0.208 adrift in the evening floodlit running on the fast street circuit and with soft tyres.
Aston Martin's Canadian Lance Stroll, still recovering from breaking both wrists and a big toe in a pre-season cycling accident in Spain, was fourth in session one and seventh in the evening.
Alpine's Esteban Ocon was fourth fastest in session two, ahead of Mercedes' George Russell who was fifth in both with teammate Lewis Hamilton sixth and 11th.
Ferrari's Charles Leclerc and Carlos Sainz were ninth and 10th in the evening after precautionary engine changes in the morning.
Leclerc will have a 10-place penalty on the grid for Sunday's race after a change of electronic control unit. Worryingly, he reported problems with the clutch in the second session.
