Okay, so I am trying to figure out the logic of Oliver thinking he can kill Slade in a one-on-one fight.
First, their skills are most likely on par with each other. However, Slade did have 5 years to get his revenge, and could have trained in other forms of fighting that Oliver may not know about.
Second, Slade's physical fighting capabilities vastly outshine Oliver's by a longshot. Slade has more power to his strikes, faster reflexes to dodge Oliver's attacks, and a quicker healing factor so that Oliver's strikes do not affect him. How does Oliver plan to overcome this?
Third, since Slade wants to destory Oliver, so how does Oliver know that Slade does not have some backup plan (e.g. Slade could have a clip go over the Internet showing how Oliver Queen is the Arrow, thus critically damaging him) if Oliver defeats him?
Fourth, fighting is most about your zeal to win. I would have to say that Slade has a stronger zeal that Oliver's, as he is seeking to get revenge.
Fifth, Oliver stated he would permanetly kill Slade in their fight. However, even if Oliver somehow beats Slade, how does he know that he could actually kill him? I mean, on the Island, he put an Arrow through his eye, and yet Slade survived.
So, all in all, why does Oliver think he has a chance to defeat and kill Slade in a one-on-one confrontation?
Let me know your theories and suggestions in the comments below!