Tuesday night will be the last time two Washington fans attend a game at Nationals Park for the foreseeable future ... 'cause the team has reportedly just banned the men for five years after they were accused of heckling Cubs star Willson Contreras.
The incident happened in the top of the 10th inning of the Nats vs. Chicago tilt in D.C. ... when following a sacrifice fly, two guys in Nationals jerseys appeared to say things to Contreras that rattled the Cubs catcher.
Video from the stadium shows the 30-year-old was pissed on the diamond -- and stayed mad for several minutes in the dugout, before the fans were eventually escorted away from the area.