WATCH: Classic ⚾: The Big Unit tosses perfect game

Arizona Diamondbacks left-hander Randy Johnson had already accomplished so much by the 2004 season.

But only a few short months before his 41st birthday on May 18, 2004, the Big Unit crossed out the biggest individual accomplishment a pitcher can achieve. Facing the Atlanta Braves, Johnson threw the 17th perfect game in MLB history, and the first since David Cone's in 1999. He also became the oldest pitcher to throw a perfecto.

Watch the historic outing below: