Day of the Fight and Raging Bull
I am a boxing fan and a Kubrick fan. This was real boxing match, but many shots were recreations due to multiple cameras and the artistic angles capturing closeup action, even sometimes from within the ring itself; particularly the shot trough the stool as the bell sounds, and the other too good to be true shots.
The most memorable I feel is the shot from the canvas upward in between both fighters as they exchange in close quarters. This reminded me a lot of similar footage in Raging Bull by Scorsese. When I saw Raging Bull in the theater I thought this had not been done before in a movie, but sure enough it had.