Valtteri Bottas took over from Mercedes AMG Petronas Formula One Team team-mate Lewis Hamilton in the afternoon of pre-season testing two, day one, and completed a respectable 86 laps in the W08.
His best time of 1:20.924 placed him fifth, one place behind Hamilton and 1.2 seconds slower than former Williams Martini Racing team-mate Felipe Massa.
The Finn undertook tyre analysis and set-up work during his long run in preparation for the season opener in Melbourne later this month.
“We managed to complete more mileage – more than 80 laps in four hours – which is good,” he said. “We’re still focusing on the long runs and doing setup changes and learning about the car, so it was a valuable day.
“We haven’t quite got to the point where we want to be yet. There’s always work to do with the car and we’re evaluating all the upgrades – what’s good and what’s not good – and seeing in what areas we still need to improve.”
Despite both Red Bull Racing and Scuderia Ferrari outpacing the Silver Arrows, Bottas suggested that Mercedes’ true pace has not yet been revealed, and is being held in reserve whilst their attention is devoted to other matters such as race preparation.
“We’re not looking at lap times right now, but we can beat the 1:19:705 we set last week if we want to, it’s definitely possible,” he added. “I think Ferrari are looking very good – they seem to be consistent and fast. We shouldn’t underestimate them or Red Bull.
“We’ll need to keep working hard to be in the best shape possible for Melbourne.”