The climactic 8 Mile rap battle sees Eminem’s B-Rabbit finally getting the best of Anthony Mackie’s Papa Doc and Eminem’s final rhymes are brilliantly inspired by Mackie’s real life. A semi-autobiographical portrayal of Eminem’s early rap career, 8 Mile was a critical and commercial success. Mackie appears in the 8 Mile cast as Papa Doc, the leader of the ‘Free World’, a rival crew to B-Rabbit and his friends. He is an intimidating villain, beating up Rabbit at one point. However, 8 Mile ends on their final rap battle, where B-Rabbit takes Papa Doc down with a scathing reveal.
https://screenrant.com/anthony-mackie-8-mile-eminem-final-rap-battle-real-life/