The only real flaw in Mercedes’ title-winning 2018 season was the performance of Valtteri Bottas. That is the view of F1 sporting boss Ross Brawn. An experienced team boss after his time with Ferrari and Mercedes, Brawn praised Toto Wolff for upping the German team’s game in the face of the stronger challenge put up by Ferrari. “The only slight flaw, if there can be one in a season like this, was the performance of Valtteri Bottas,” Brawn said.