Pierre Gasly headed the practice session for GP2's return to Malaysia.
The Frenchman set a time of 1 minute 42.352 seconds to beat Prema team mate Antonio Giovinazzi who currently sits 10 points behind him in the standings.
Hometown hero Nabil Jeffri could only manage 18th after a spin, while Mitch Evans 11th place made him the highest ranking driver to previously race GP2 at the circuit, having finished on the podium at the series' last visit in 2013.
Bahrain International Circuit - Winter testing
Would you like to stay up to date with the latest Lewis Hamilton and Formula 1 news from GPtoday? Activate free push notifications and be the first to know!