America's newest F1 driver Sargeant impressed for Williams, finishing just 0.063secs slower than Sainz's effort, albeit on the softer C5 tyres.
Alonso continued his impressive form for Aston Martin to finish third on the same tyre compound as compatriot Sainz, four-tenths adrift. The two-time champion returns to the car in the afternoon session.
Alfa Romeo's Zhou Guanyu was next on the timesheets, though his lap count was down on the rest of the field with only 43 laps to his name.
Midfield forming?
Kevin Magnussen was fifth for Haas despite the apparent stiffness of the VF-23 chassis. The Dane and team-mate Nico Hulkenberg have struggled with front locking more than any others so far.
Esteban Ocon took on morning duties for Alpine after running in the evening on the first day, and finished sixth ahead of Sergio Perez, who ran in a change of plan for Red Bull.
Verstappen was slated to complete the morning before handing over to Perez for the rest of the test, but the Mexican instead took the early session to allow his team-mate the opportunity to practice in representative conditions under the lights ahead of round one.
Chaos averted
Lewis Hamilton completed over 70 laps for Mercedes despite losing time in the garage after shedding bodywork from the floor of the W14.
McLaren was ninth fastest with Lando Norris at the wheel whilst Yuki Tsunoda rounded out the times, another to struggle with bodywork damage from bumps and kerbs in the AlphaTauri.
The session ended with a red flag procedure test, with cars returning to the pits before completing an out lap, an aborted start procedure and a full start from the grid.
But with Sargeant and Norris, second and third on the practice grid, treating the drill as a usual end-of-practice start, when the lights went out the McLaren was almost collected by Sainz.
Hamilton was also forced to stop in his tracks as carnage was only narrowly avoided.
It's lights out and away we go - Anthony Davidson edition 😂