After securing his fifth constructors' title as team principal of Mercedes on Sunday, Toto Wolff has labelled his team's 2018 campaign as its toughest yet.
Mercedes wrapped up the constructors' championship at Interlagos following Lewis Hamilton's tenth victory of the season and Valtteri Bottas' fifth-place finish. Going into Brazil, title rivals Ferrari had to outscore Mercedes by 13 points to take the fight to the season finale in Abu Dhabi, but could only manage third and sixth -- losing 12 points to Mercedes overall.