Even if the timesheets could be easily dismissed, with teams running different programmes, there was no denying that the new Red Bull already looked a step up from last year's dominant RB19.
Verstappen was comfortably faster than the quickest lap of the opening day of testing last year, completing 143 laps - two race distances - and wrapping up 1.140 seconds clear of closest rival Lando Norris in the McLaren.
The Dutch driver's best lap of one minute 31.344 seconds under the evening floodlights compared to last year's opening day best of 1:32.837 at the same circuit.
"It feels good to be back in an F1 car again and I had fun out on track today," said Verstappen.
"We covered a lot of laps and tried quite a few things with the car, which was important, so happy overall with how it went.
"After the winter break, the first few laps always surprise you a little but then you get back into the swing of things pretty quickly."
The sense of business as usual contrasted with the uncertainty surrounding Verstappen's team boss Christian Horner, who has denied allegations of inappropriate behaviour levelled against him by a female employee.
Verstappen, who won a record 19 of 22 races last season with Red Bull's Sergio Perez winning two more, was also top of the morning session in 1:32.548 when he completed 65 laps without any problem.
"We came to Bahrain with a few unknowns around a relatively new car but we have tested most of the fundamentals on day one and got the answers we needed to," said his race engineer Gianpiero Lambiase.
PRODUCTIVE FERRARI
Ferrari's Charles Leclerc was second in that one with Fernando Alonso third for Aston Martin and the last driver within a second of Verstappen.
"Our first morning of testing was quite productive, especially in terms of mileage," said Leclerc. "As for the performance, it's just too early to comment or draw conclusions.
"We ran all the tests we planned to and things are going ahead as expected, which is a positive."
Australian Oscar Piastri lapped fourth fastest for McLaren, handing over to Norris for the second stint.
Alex Albon of Williams was the first driver to experience any notable problem, stopping his car on track due to a fuel pump problem with 21 minutes remaining of the first session. Team-mate Logan Sargeant had a suspected driveshaft problem later on.
Mercedes had George Russell in their car, whose front wing gained plenty of attention, all day with seven-time world champion Lewis Hamilton driving on Thursday.
Team boss Toto Wolff said the mood in the team was positive, with Mercedes putting the emphasis on creating a stable platform for development and spending time making changes to the car in the garage.
"We had a filming day yesterday and then some aero running this morning with no relevant lap times," added the Austrian.
"So far the feedback from the drivers was yes, this is something we can start to work with and that is encouraging."
Teams have only three days of testing before the season starts in Bahrain next week.