kakashi was a jonin at 13
I'd only say Kakashi because Kakashi is naturally adapt for killing Sasuke. Think about it. Sasuke's lightning jutsu's are weaker than Kakashi's and his fire jutsu's won't work against Kakashi's water techniques. That only leaves his mangekyou sharingan techniques. Kakashi's extremely skilled with genjutsu so Sasuke couldn't very well rely on that and I doubt he's faster than Kakashi. It would come down to if the Amaterasu could beat Kakashi's dimension technique. And I'm pretty sure that's how Sasuke extenguished the Amaterasu. Because of that, I think it would come down to the fact that Kakashi is just more intelligent than Sasuke and would out strategize him.
Better in what sense & way?
If you mean battle strength, probably Sasuke is stronger, cause now he has new eyes and he was trained in dark jutsus by Orochimaru for sure, not to mention the uchiha blood >.>
still he lacks Kakashi's experience.
Now, in ways of wisdom, cleverness, strategy, and of course emotions there really isn't a comparison between them. Kakashi can "feel" ^^
Sasuke is Better... He Took out a Sannin...
you mean Orochimaru???
who was practically half dead, in pain, bleeding and unable to fight even a normal chuunin in his current state? :|