F1 winter testing report: Vettel goes fastest as Mercedes fail with engine issue

Mercedes endured a disastrous eight hours in the penultimate day of F1 winter testing in Barcelona. After Valtteri Bottas had some troubles in the morning, Lewis Hamilton took over in the afternoon session and spent the first hour in the garage. When Mercedes finally sent out the six-time Formula 1 world champion, he broke down on the track with an oil pressure issue. Meanwhile, Sebastian Vettel and Ferrari topped the timesheets.

The Hamilton breakdown marks the fourth time a Mercedes engine has had serious trouble in Barcelona this season, with Williams also stopping out on track. With just one day of testing left before the teams head to Australia, Mercedes mechanics have some overnight work on their hands.

Meanwhile, Vettel set the fastest time with a 1:16.841. The Ferrari car was fitted with the C5 tyres, the softest rubber in Pirelli's range and therefore fastest. The next best time, set by Pierre Gasly, was recorded on slower tyres but was only two-tenths behind in his AlphaTauri.

It's unconfirmed what fuel levels Ferrari were running with or what engine mode they were using.

During the afternoon session, teams opted to test their cars with long runs. The lack of red flags has helped boost the amount of data collected. Nicholas Latifi had his best day in a Formula 1 car. His fastest time was a 1:17.313.