The bizarre scene unfolded in the first inning of the Pinstripes' matchup with the Dodgers at Yankee Stadium ... when Gleyber Torres hit a pop fly down the first-base line.

As the ball came crashing down, it landed in foul territory, though Betts was still able to snag it with his glove before it hit fans' hands. Yet right after he secured it in his webbing, two Yanks supporters attempted to wrestle it away from him.

Check out the video ... one man grabbed Betts' glove and tried to pry it open -- while the other took hold of his throwing hand. Eventually, the ball popped free -- and Betts was livid.

The umps, however, still ruled it a catch and called Torres out. The two fans could be seen minutes later being escorted out of the area.

Austin Capobianco, one of the men reportedly involved in the play, explained his side of the situation to ESPN from a nearby bar later in the evening.

"We always joke about the ball in our area," Capobianco told the outlet. "We're not going to go out of our way to attack. If it's in our area, we're going to 'D' up."

"Someone defends, someone knocks the ball. We talk about it. We're willing to do this."

Capobianco added that while he and his pal were ejected from Game 4 -- he was told they'd be allowed back for Wednesday's Game 5.