George Russell set the fastest time for Mercedes, as the Bahrain test concluded on Wednesday.
The Williams driver, who is also a Mercedes junior, moved to the top of the timesheets in the final 10 minutes of running with a 1m29.029s on the C5 tyre.
Without the rain that interrupted the action on Tuesday, lap totals were also much improved with the Briton one of seven drivers to exceed 100 laps on the day.
Sergio Perez also used the softest compound available claim P2 for Racing Point as Sebastian Vettel, who had led the way in the morning, slipped back to third in the afternoon.
Carlos Sainz managed quite possibly a first for an F1 test by featuring twice on the timesheet in P4 and P16.
This is because he ran in both the McLaren test car and in the car which Pirelli used to conduct tyre development, with his best time coming in the former.
Toro Rosso also ran two cars with Daniil Kvyat fifth and Alex Albon seventh, the Thai driver would achieve the most mileage of the day with 143 laps to his name.
Mick Schumacher would manage just less than half that with 70 laps in the Alfa Romeo, having moved from running for Ferrari on Tuesday, and the 2-year-old would split the two Red Bull juniors in P6.
Lance Stroll was eighth after a shortened morning, just ahead of Dan Ticktum who finally got his big F1 test chance with Red Bull.
The Briton would manage 135 laps on an impressive first day, finishing P9.
Haas again split their running between Romain Grosjean and Pietro Fittipaldi with the Frenchman only three-tenths clear of the Brazilian in P10 and P12 respectively.
Fernando Alonso’s test return ended with another 69 laps in the afternoon as part of the McLaren being operated with Pirelli in P11.
Lando Norris was P13 ahead of Renault development driver Jack Aitken with Nicolas Latifi bringing up the field in P15.
Full results from Wednesday can be seen below (Kvyat & Alonso ran a separate Pirelli test):
