[quote=@Bishop]
Sooo... can we make a master that fights on par with servants? I remember that teacher in fate ubw who was boosted by caster and almost killed saber 1v1. Or even kid Emiya could 1v1 servants.
[/quote]

Kuzuki was able to fight Saber mainly because of Caster’s aide, but also because he caught Saber by surprise. Without Caster, he wouldn’t have been able to take her on.

In Shirou’s case, it was because of Unlimited Blade Works being a hard counter to Gilgamesh along with Shirou really catching him off guard. Really, it’s Anime Protagonist Syndrome at its finest, if we have to go that far.