Fate/stay night - Season 1 Episode 4 The Strongest Enemy The Holy Grail War Begins!
Overview: After the meeting with Kirei Kotomine Shirou and Rin leave the church only to run into another Master that goes by the name of, Illyasviel von Einzbern. Saber is forced to go into combat against an incomprehensibly stronger servant, called Beserker. With Saber's previous injury still causing major problems and reducing her fighting capacity, is there even a chance of her winning?