Mercedes driver Lewis Hamilton clocked the quickest time during the opening day of the first in-season test in Bahrain on Tuesday.
Hamilton recovered from an early stoppage in the W08 to post a time of 1:31.358 on the Soft tyre, finishing 0.626s clear of Ferrari reserve driver Antonio Giovinazzi, completing 97 laps.
Hamilton's benchmark time was 2.5s slower than the lap recorded by Valtteri Bottas last Saturday to claim pole position.
Giovinazzi, who substituted for Sauber’s Pascal Wehrlein in Australia and China, logged 93 laps as he sampled the SF70-H for the first time.
Daniel Ricciardo’s running for Red Bull came to a premature end when he stopped at Turn 1 during the afternoon due to a power unit issue, limiting him to 45 laps, while Romain Grosjean went fourth for Haas.
Williams split its running between Felipe Massa and Lance Stroll, who placed fifth and seventh respectively, sandwiching Renault’s Nico Hülkenberg.
Formula 2 racer Sean Gelael stepped into Formula 1 machinery for the first time with Toro Rosso and recovered from two early stoppages to place eighth, 2.5s off the pace, completing 78 laps, the first of three planned runs this season.
Ferrari’s Sebastian Vettel, conducting tyre testing with Pirelli, will continue running until 21:00 local time after losing track time earlier in the day with a reliability issue, but finished the group session ninth on the leaderboard.
Force India development driver Alfonso Celis Jr. returned to action in the VJM10, having previously sampled the car pre-season, and placed 10th, as Sauber’s Marcus Ericsson logged the most laps, 106, to finish 11th.
The beleaguered McLaren-Honda outfit endured another challenging day, with Oliver Turvey stranded in the garage for much of the day after a water leak from the ERS was detected.
McLaren had to conduct a power unit change, meaning Turvey only re-appeared during the final hour, and finished at the foot of the times, 3.6s off the pace, having completed the fewest laps (16).
| Pos. | Driver | Team | Time | Gap | Laps |
| 1 | Lewis Hamilton | Mercedes | 1:31.358 | 97 | |
| 2 | Antonio Giovinazzi | Ferrari | 1:31.984 | 0.626 | 93 |
| 3 | Daniel Ricciardo | Red Bul | 1:32.349 | 0.991 | 45 |
| 4 | Romain Grosjean | Haas | 1:33.452 | 1.094 | 87 |
| 5 | Felipe Massa | Williams | 1:32.509 | 1.151 | 56 |
| 6 | Nico Hulkenberg | Renault | 1:33.624 | 2.266 | 74 |
| 7 | Lance Stroll | Williams | 1:33.729 | 2.371 | 35 |
| 8 | Sean Gelael | Toro Rosso | 1:33.885 | 2.527 | 78 |
| 9 | Sebastian Vettel | Ferrari | 1:33.894 | 2.536 | 89 |
| 10 | Alfonso Celis Jr | Force India | 1:33.939 | 2.581 | 70 |
| 11 | Marcus Ericsson | Sauber | 1:34.550 | 3.192 | 106 |
| 12 | Oliver Turvey | McLaren | 1:35.011 | 3.653 | 17 |
