His Mercedes team said it. But he also said that he thought the gap between his Mercedes team and Ferrari was "potentially half a second, something like that". Everyone who knows anything about Formula 1 knows that pre-season testing times are an unreliable guide to actual performance. In 2018, although Ferrari topped the list of fastest times, Mercedes had done quicker race simulations, which is not the case this year. One of the reasons the Mercedes race simulations were slower than Ferrari's was that they were suffering more from 'graining' - where the surface tears, reducing grip.

Source: BBC March 01, 2019 21:33 UTC