Freddie Freeman's walk-off Grand Slam home run in game one was the swing that set the tone for the eventual World Series champions ... and now the ball just sold at auction for $1.56 million!
The whopping price tag makes the Freeman ball the third most valuable in the history of baseball -- coming in behind Shohei Ohtani's 50th HR ball and Mark McGwire's 70th HR ball from 1999.