But considering all circumstances the results are really explicable.Sure.
Still, he managed to leapfrog ranks he wasn't expected to.
None of the top TT guys was at his best today (aparat from Kung who imho went too hot at some point and could've won that) plus some (WvA, Roglic) were absent. Foss who's a solid TTst showed up in excellent form with super fresh legs and great knowledge of the course. And he won.
So I'd say a huge surprise, but not so much if you look closer at it.