Originally Posted by jedispy
You mean when Obi Wan defeated Maul vs. when Anakin failed to defeat Obi wan?
I think it comes down to the fact that in both occasions Obi Wan's mind was at peace. As Yoda said the light side is stronger than the dark side. The dark side is only quicker, easier, and more seductive.
What peace of mind? He was full of anger and made a flying leap against an opponent who had the high ground. Only he succeeded and Anakin failed.