The bomb to deep centre off of pitcher Will Warren put the Dodgers up 7-0 in the bottom of the second inning - before extending their lead to 10-0 following Muncy's home run.
It was Muncy's fifth homer of the season and raised his RBI total to 28 after also bringing in a run with a single in the first inning.
Muncy wasn't the only big-name third baseman to reach 200 career home runs this season, as Red Sox's Alex Bregman also accomplished the same feat earlier this month.
It hasn't been the greatest season for the 34-year-old lefty. He's currently slashing .219/.343/.710 after his first two at-bats on Saturday, recording 51 strikeouts to just 37 hits.
Muncy is currently in his 10th season in the big leagues, where he spent the first two with the Athletics before going on to be part of the Dodgers for the next eight years, including this season.
UPDATE: Muncy hit his second home run of the game to extend the Dodgers' lead to 14-1.