Esteban Ocon set the pace in GP3 practice on Thursday morning, the ART driver going to the top with a late flier in scorching conditions at the 15-turn, 3.363-mile Bahrain International Circuit.
CLICK: Full GP3 practice times from Bahrain
It's the first time that GP3 has been to Bahrain, in a replacement round organised after the cancellation of the original weekend that was to have taken place in support of the German Grand Prix in the summer.
When financial circumstances saw that event fall through, the GP3 and GP2 Series organised a stand-in event in Bahrain, where it's taking place alongside the Six Hours of Bahrain endurance event rather than the usual F1 race.
It also means a very different schedule that usual, with practice and qualifying taking place on Thursday, race 1 on Friday morning, and race 2 on Saturday morning.
Early in the 45-minute practice session, Carlin's Jann Mardenborough was first into the 1:48s range but was quickly ousted by Jenzer Motorsport's Mathaeo Tuscher. Then it was Artur Janosz' turn to go to the top in the Trident, and he held sway over the timing screens for much of the remainder of the session as teams turned their attentions to race distance set-ups.
A late flurry of qualifying laps changed the picture before the chequered flag came out, with series newcomer Matevos Isaakyan briefly going a second faster than the rest of the field to go top in his first GP3 outing substituting for Adderly Font in the Korainen GP #10, but he quickly muscled aside by an improved effort from ART's Marvin Kirchhöffer.
However once the desert dust settled, it was Ocon who had succeeded in setting the top time of 1:47.121s which put him over a third of a second clear of Korainen GP's Matt Parry with Carlin's Antonio Fuoco going third ahead of Kirchhöffer.
Ocon is currently just two points behind Trident's Luca Ghiotto in the drivers championship standings with just two rounds left to go in Bahrain and Abu Dhabi. Ghiotto was only tenth fastest in practice on Thursday, and was 1.850s slower than Ocon in this session.
A crucial qualifying - with four points available to whoever wins pole - now follows at 12:40pm local time (9.40am GMT) after GP2 practice.
See full GP3 practice times from Bahrain