Harper unleashed a flurry of punches after appearing to be deliberately targeted by Giants relief pitcher Hunter Strickland in the eighth inning of the Nats' 3-0 win at AT&T Park.
It was the first meeting between the two men since the 2014 playoffs, when Harper blasted Strickland for two consecutive home runs.
In Monday's Memorial Day game, Strickland made his intentions plain with his first pitch, plunking Harper with a stinging ball to the midriff.
Harper immediately responded, ripping his helmet off in disgust and charging the mound to exchange punches with Strickland.
As the two players slugged it out, both benches cleared and Harper was eventually pulled away as the ugly melee continued.
Both Strickland and Harper were ejected from the game and are now likely to face disciplinary action from Major League Baseball chiefs.
Last year, Baltimore Orioles slugger Manny Machado received a four-game suspension for charging the mound after being hit in the back by Kansas City Royals pitcher Yordano Ventura, who died in January in a car accident.
source: news.abs-cbn.com
