Photo: Sam Bloxham/GP3 Series Media Service
Esteban Ocon led the way as GP3 cars lapped the Bahrain circuit for the first time in free practice ahead of the penultimate round of the season.
The Frenchman, who is just two points behind championship leader Luca Ghiotto, went to the top of the times with a couple of minutes left on the clock.
He displaced his ART team-mate Marvin Kirchhofer, who was pushed back to fourth before the end by Matt Parry and Antonio Fuoco.
Matevos Isaakyan, driving a GP3 car for the first time after being drafted in at Koiranen, had gone quickest with five minutes remaining and was still a creditable sixth at the flag behind Mitch Gilbert.
In his second GP3 appearance with Campos, Konstantin Tereshchenko was seventh ahead of Artur Janosz, the leader for much of the session.
Matheo Tuscher, on double duty this weekend in both GP3 and the World Endurance Championship, was ninth with Ghiotto 10th.
Practice session results
| Pos | Driver | Team | Time | Gap | Laps |
| 1 | Esteban Ocon | ART Grand Prix | 1:47.121 | 16 | |
| 2 | Matt Parry | Koiranen GP | 1:47.464 | 0.343 | 19 |
| 3 | Antonio Fuoco | Carlin | 1:47.799 | 0.678 | 19 |
| 4 | Marvin Kirchhofer | ART Grand Prix | 1:47.913 | 0.792 | 16 |
| 5 | Mitch Gilbert | Carlin | 1:48.192 | 1.071 | 17 |
| 6 | Matevos Isaakyan | Koiranen GP | 1:48.443 | 1.322 | 17 |
| 7 | Konstantin Tereschenko | Campos Racing | 1:48.483 | 1.362 | 18 |
| 8 | Artur Janosz | Trident | 1:48.893 | 1.772 | 19 |
| 9 | Matheo Tuscher | Jenzer Motorsport | 1:48.949 | 1.828 | 10 |
| 10 | Luca Ghiotto | Trident | 1:48.971 | 1.850 | 17 |
| 11 | Jann Mardenborough | Carlin | 1:48.998 | 1.877 | 20 |
| 12 | Jimmy Eriksson | Koiranen GP | 1:49.013 | 1.892 | 19 |
| 13 | Kevin Ceccon | Arden International | 1:49.082 | 1.961 | 17 |
| 14 | Ralph Boschung | Jenzer Motorsport | 1:49.241 | 2.120 | 17 |
| 15 | Pal Varhaug | Jenzer Motorsport | 1:49.283 | 2.162 | 19 |
| 16 | Alex Bosak | Arden International | 1:49.504 | 2.383 | 16 |
| 17 | Alex Palou | Campos Racing | 1:49.624 | 2.503 | 21 |
| 18 | Emil Bernstorff | Arden International | 1:49.631 | 2.510 | 10 |
| 19 | Alex Fontana | Status Grand Prix | 1:49.669 | 2.548 | 17 |
| 20 | Zaid Ashkanani | Campos Racing | 1:49.702 | 2.581 | 14 |
| 21 | Michele Beretta | Trident | 1:49.729 | 2.608 | 16 |
| 22 | Seb Morris | Status Grand Prix | 1:49.795 | 2.674 | 17 |
| 23 | Sandy Stuvik | Status Grand Prix | 1:49.911 | 2.790 | 18 |
| 24 | Alfonso Celis | ART Grand Prix | 1:50.606 | 3.485 | 10 |