The two-and-a-half-hour session saw two red flags – both for harmless spin-and-stalls by Felix Rosenqvist of Arrow McLaren-Chevrolet and Helio Castroneves of Meyer Shank Racing-Honda.
With his 17th lap, Herta became the first driver to crack the 100sec barrier with a 1min39.9303sec effort, an average of 110.489mph.
