The amazing thing to me about Russell's Celtics beyond just the 11 out of 13, is the fact that nearly his entire career Wilt Chamberlin was in the NBA. The fact that Wilt only got the best of Russell once in all those years in an 8 team league is absurd.
And the fact that only once during that period did a coach or organization not manage to find a way with Wilt. Russell and the Celtics just beat him with team, running, and Wilt just got his basically. It is astonishing to me that Wilt did not have more success in an 8 team league. It speaks even more to the greatness of those 60s Celtics teams.