13:12 – Toro Rosso debutant Brendon Hartley believes he made substantial progress through the course of Friday’s practice sessions in the United States, as he got to grips with the STR12.
Porsche sportscar racer Hartley has been drafted in by Toro Rosso in place of Pierre Gasly, who opted to compete in the Super Formula finale, which has since been cancelled due to a typhoon.
Hartley, having not piloted a single-seater car in five years, completed 69 laps over the three-hour practice period, winding up 17th quickest, his best lap 1.2s shy of team-mate Daniil Kvyat.