As it stood, Houston managed only one hit -- an RBI double by Jose Altuve -- at Coors Field.
Leading off the sixth, Bregman cruised into third with an apparent triple off the wall that eluded the leap of Colorado left fielder Gerardo Parra.
Rockies manager Bud Black challenged for fan interference, and Bregman was ruled out after replays showed a spectator clad in an orange Astros jersey extended his glove over the railing enough for the ball to glance off it, changing its trajectory slightly at the moment Parra was reaching up to attempt the catch. The fan was escorted out of the ballpark by security.
According to MLB rules, if fan inteference "clearly prevents a fielder from catching a fly ball," the batter will be declared out.
After the game, Bergman blasted the umpires over the ruling.
"It changed the whole f---ing game. We're up 2-1 at the time, I'm at third base. We need a fly ball to the outfield to get me in, and it's 3-1."
There was more weirdness in the seventh inning.
Colorado tied the score at 2-all thanks to heads-up baserunning by Raimel Tapia, who tagged up and scored from third when Astros third baseman J.D. Davis sprinted toward the Houston dugout and tumbled over the railing as he caught Nolan Arenado's foul pop.
Davis' teammate Evan Gattis helped him break his fall and pushed him back over the railing and onto the field, but Davis' hurried throw home was off target as Tapia slid into the plate.
Information from The Associated Press was included in this report.