You behaved just like funnyone in a post a month or two ago where I critiqued his dagger tactics. I repeat them for you and hope you take them to heart.
Artery is absolutely the last thing you should be using to start this and almost all fights. 99% of your fights should be opened by hamstring or hurl. Why? Because hamstring cannot be done in combat (while tanking, as you are when you attack first). Hamstring not only causes bleeding but hits the movement which might have helped when the muter was constantly fleeing in that wooded area and then moving to summon you. Hurl, while possible both as an opener and during combat, only has 1 round of lag when used as an opener vs 2 rounds of lag if you're already fighting. Classic opening is Hamstring, flee, hurl, artery for full blood/str loss, and then if you want you can flee/underhand or just stay and continue fighting, depending. There are times to change that up but you should be in the habit of starting fights with hamstring or hurl. Get out of the habit of starting with artery.
Also, if you are going to underhand, you should be dual wielding daggers. If you plan to use a shield, better to start with something else, you aren't going to get much use and you get stuck with the full lag.
Hope that helps. I look forward to seeing a log of you kicking the necro's bony ass.