SAKHIR, Bahrain – After a rocky start to preseason testing, Valtteri Bottas put Mercedes AMG Petronas back on top of the Formula One time sheets Saturday at Bahrain Int’l Circuit.

Bottas lapped the 3.363-mile, 15-turn circuit in 1:30.289 with his No. 77 Mercedes W12 to lead the 16 drivers that turned at least one timed lap during the second day of F-1 testing.

Bottas’ best lap of 58 total was turned on the softest Pirelli tire compound available, the C5 compound.

“It was a lot better for me than yesterday, for sure,” said Bottas, who battled gearbox issues on Friday in Bahrain and only completed six laps. “I finally managed to get some laps and some clean runs to really learn about the new car and try some things. It’s always good when you learn and that’s what testing is all about – the opportunity to run different things and see how the car reacts. As a driver you use that information in a race weekend so it’s hugely important. If the set-up changes work or don’t work, it’s all valuable information.

“For sure it’s windier here than we’ve had at a race, but one of the bigger issues with the car is the rear end; it’s quite snappy and unforgiving,” Bottas added. “With the new tires, it’s quite sensitive, so we need to calm the car down a bit.”

Though Bottas was pleased with his pace, he admitted that leading testing this early in the game isn’t necessarily indicative of what the season will hold.

“It’s so difficult to say what that means. I can’t be jumping around happy because it is only testing,” Bottas noted. “As always, we are just focused on getting through our program and maximizing the learning. You never know what fuel loads people are running. Hopefully by the end of tomorrow, we will have a better idea of where we are.

“Testing is limited and a lot more compromised this year for everyone, because you have less time in the car before the first race. I would be happy if we could just get through the final day tomorrow nice and clean,” he added. “Today felt good and the times were pretty fast, so I just want more laps and more feeling with the car.”

Pierre Gasly was second for AlphaTauri at 1:30.413, with Aston Martin’s Lance Stroll third at 1:30.460. McLaren’s Lando Norris and Alfa Romeo’s Antonio Giovinazzi were fourth and fifth fastest, respectively.

Ferrari’s Charles Leclerc, Williams’ Nicholas Latifi, Red Bull’s Sergio Perez, McLaren’s Daniel Ricciardo and Alpine’s Fernando Alonso completed the top 10 runners.

Bottas’ Mercedes teammate Lewis Hamilton was 15th fastest of the 16 drivers that tested Saturday, after a spin at turn 13 hampered Hamilton’s early efforts.