The boxers never liked each other and used to constantly exchange pleasantries in the media. But for an athlete to progress, sparring with strong partners is necessary. Ultimately, Jay Deese, Wilder's manager and assistant trainer, arranged for him to spar with Miller without warning.
“This guy used to laugh at me. One day I come to training, look, and Miller is there waiting for our sparring. I didn’t even listen to all the nonsense that the coaches told me before the sparring, I just wanted to get into the ring as quickly as possible. Throughout the entire sparring I beat him and talked to him constantly. I treated this sparring like a real fight. Miller ended up in the hospital with a concussion afterward,” said Wilder, who held the WBC heavyweight throne for more than five years.