I would say that one distinct part of the definition in creating a parallel between the struggle against Apartheid and the Civil Rights Movement is that both were movements of profound change. The parallel between both movements is that they sought to transform what was into what could be. The Civil Rights Movement focused on defeating the structures of racism that existed in American social, economic, and political realities. The Civil Rights Movement understood that there were entrenched interests that stood united against the desire for inclusion and change. It was to this end that the Civil Rights Movement galvanized individuals into action. In much the same way, Nelson Mandela and the individuals who waged war against Apartheid understood their adversary in the same manner. Change would not be easy to realize in both settings. The need to foster intense commitment to profound change is paralleled in both movements. It can help to define one aspect of similarity between them.
Another part of defining the parallel between both movements is in the need for charismatic leaders who were not afraid of sacrifice. In the Civil Rights Movement, leaders like Dr. King, Malcolm X, or Stokely Carmichael were essential agents of change. They sacrificed much for their visions and were able to communicate this level of commitment to followers. In much the same way, committed leadership was the only way that the institutionally embedded nature of Apartheid was to be overcome. Nelson Mandela is one such example of committed leadership that sacrificed mightily for his beliefs and vision. Mandela's leadership, even when imprisoned, was a significant reason for the dismantling of Apartheid. Another aspect of describing the parallel between both the Civil Rights Movement and the struggle against Apartheid was the presence of committed and inspiring leadership.