Ricciardo fastest on Saturday morning of F1 test, Hamilton spins

Shortly past the halfway point in the four-hour morning session Hamilton lost the rear of his Mercedes W12 in Turn 13 and slid backwards into the gravel trap. Hamilton got beached, bringing out a 15-minute red flag and forcing the world champion to have his car towed back to the pitlane.

Hamilton returned to the track before the start of the fourth hour and recovered to turn a healthy 58 laps, but the incident meant Mercedes lost more precious track time after teammate Valtteri Bottas only managed six laps on Friday morning due to a gearbox issue.

The seven-time world champion was one of many drivers to go adrift on the ever-dusty Bahrain international Circuit, with Williams driver Nicholas Latifi spinning off at Turn 7 and Ferrari's Carlos Sainz also going for an off-track excursion.

At the top of the leaderboard Sainz had put down a first marker with a 1m33.072s lap on mediums.

Alpine's Fernando Alonso, who made his first appearance since fracturing his jaw in a cycling accident, soon dipped below Sainz' time with a 1m32.769s on hard tyres.

Alonso and the man he replaces at Alpine, McLaren's Ricciardo, then traded fastest times during the second hour. Ricciardo, who was also fastest on Friday morning, re-took top spot with a 1m32.215 on mediums, one tenth quicker than Alonso's quickest lap.

After the mid-session red flag Latifi jumped to third, only to be displaced by Sergio Perez. The Mexican took third with a hard tyre lap of 1m32.478s on his first Red Bull appearance.

Latifi used Pirelli's softest C5 compound to grab fourth, followed by AlphaTauri's Yuki Tsunoda and Sainz. On soft tyres Nikita Mazepin was seventh for Haas ahead of Hamilton, whose fastest time was 1.1s slower than Ricciardo.

Alfa Romeo's Antonio Giovinazzi didn't set a competitive time in ninth but - more importantly - enjoyed a productive morning in the C41. His tally of 73 completed laps was just two short of lap chart leader Mazepin.

Aston Martin's Sebastian Vettel was tenth and last after sitting out most of the morning session. In a repeat of Bottas' woes on Friday, the German only managed six laps before encountering a Mercedes gearbox issue on his AMR21.

Aston managed to get Vettel back out shortly before lunch for three more laps, but a second red flag with five minutes to go - for a race control systems test - then brought the session to a close.

The chequered flag marked the halfway point of F1's pre-season test at Sakhir, with testing to resume at 15:00 local time on Saturday ahead on Sunday's final test day.