Bahrain: Mercedes' Valtteri Bottas began the team's recovery after a difficult start to pre-season testing by setting the fastest time on day two in Bahrain, though team mate Lewis Hamilton brought out a red flag after a spin in the morning.
Bottas went top of the timesheets with a lap of 1m30.289s - though he did so using the softest C5 tyre compound, and with just 20 minutes of the session remaining when the track was at its fastest, so the Silver Arrows may still have work to do after a gearbox issue saw them miss almost all of the morning's running on Friday.
It initially didn't get much better for the reigning champions with Hamilton finishing 15th fastest after his morning appearance, with a spin at Turn 13 that brought out a 15-minute red flag.
After qualifying simulations began with an hour left of the day under the floodlights, runner-up Pierre Gasly briefly led, and ended up 0.124s behind Bottas on the same tyre. The AlphaTauri driver shared the car with Yuki Tsunoda, who finished 11th after running in the morning.
Fourth-place Lando Norris also had a stint at the top of the time sheets but eventually finished fourth on soft C4 tyres. His team mate Daniel Ricciardo led the morning session and finished ninth overall using mediums.
The day's running was punctuated by two red flags, the first triggered by Hamilton's spin, and the second coming when eighth-quickest Sergio Perez’s Red Bull RB16B engine cover spectacularly dismantled as he pulled out from behind Nicholas Latifi’s Williams. Perez used hard tyres for his fastest lap.
Aston Martin's Lance Stroll finished third with a very late quick lap, but his team mate Sebastian Vettel was slowest of all, with just 10 laps completed thanks to a gearbox issue in the morning, which was fixed in time for Stroll's stint.
Alfa Romeo gave the whole day to Antonio Giovinazzi after Kimi Raikkonen drove on Friday, and the Italian completed 124 laps to finish fifth on the C5 compound.
Charles Leclerc couldn't beat the Alfa Romeo with his flying effort late on, and finished P6 on the same tyre as Giovinazzi having taken over from team mate Carlos Sainz (P13) in the afternoon. Sainz spun dramatically in the morning but managed 56 laps in total, Leclerc completing 73.
Two-time champion Fernando Alonso made his first appearance since recovering from a broken jaw sustained in a cycling accident last month, and he set 127 laps over the day with Esteban Ocon watching on. Alonso traded places with Ricciardo in the morning but the Australian came off best by a tenth in that session. Alonso managed to finish 10th overall by the end of the day.