A killing blow.
That’s what Rider’s first shot deserved to be called under normal circumstances. In terms of regular weapons of the modern era, her arrow would be like a bunker buster: a projectile bomb with possessing enough impact and perforating force to pierce the floor and destroy the underground enemy. The arrow flies in a straight line toward Alcides drilling through everything in its path.
The hide of the Nemean Lion may block any and all human constructs, but it does nothing to ward off the power of the gods that flows from girdle of Ares that serves as Rider’s Noble Phantasm, inevitably dealing internal damage.
With a direct hit, the scales would tip largely in Rider’s favor.

Fate/Strange Fake Volume 9, Chapter 31: Rhapsody of the Demigods