God damn I love this fight.
We watch Luke grow as a Jedi, force user and duelist while also realizing he's in way over his head, and perhaps should have listened to Yoda and Obi.
Vader realizing this boy is more dangerous than initially expected. I'm sure he felt pride in that.
The pacing of there conflict and the under currents of tension and the culmination of their meeting for a well choreographed battle with weight and thought behind each movement, thrust or parry they make.
So much care went into this.