Montana (5-1, 1-1 Big Sky Conference) grabbed a 7-0 lead on Bergquist's 39-yard strike to Mariani with 8:43 left in the first quarter, just one play after the Grizzlies' Severin Campbell got a hand on a punt attempt by Fritz Brayton of Eastern Washington (2-4, 1-2).
With a sweeping wind limiting each offense to just one field goal over the next two quarters, the Grizzlies went up 17-3 early in the fourth.
Andrew Schmidt broke through the line to block another Brayton punt and Erik Stoll recovered on the Eastern 8-yard line. On the ensuing play, Bergquist hit Mariani again -- his ninth TD reception of the season.
Montana went up 19-3 with 6:21 left in the game when Eastern Washington quarterback Matt Nichols was called for intentional grounding from his own end zone. Nichols, who entered the game averaging nearly 344 yards passing with 12 touchdown passes, was limited to 19-of-45 for 191 yards.
Bergquist finished 15-of-25 for 199 yards for Montana, which had no turnovers after giving up the ball nine times in its previous two games.
Mariani caught five passes for 118 yards for the Grizzlies, who have won three straight against the Eagles and five of the last six meetings between the teams.
Eastern Washington had a chance to strike first, marching the opening kickoff to the Montana 25. Running back Alexis Alexander raced 22 yards on a sweep before fumbling into the end zone, where it was recovered by the Grizzlies' Shann Schillinger.
Defensive end Greg Peach had four sacks for Eastern.
South Carolina AD Ray Tanner is not "100 percent sure" Saturday's game vs. No. 7 LSU will be played at Williams-Brice Stadium because of devastating floods that hit the state.
UCLA junior linebacker Myles Jack has withdrawn from school and will enter the NFL draft, making the decision just weeks after suffering a season-ending knee injury.
The Oklahoma State Cowboys' defense has lost senior middle linebacker Ryan Simmons for the season because of a knee injury.
A judge has dismissed simple assault charges against Rutgers wide receiver Leonte Carroo after the woman he allegedly attacked after a football game said she didn't want to testify.
Colorado coach Mike MacIntyre said he was sorry for getting into a sideline altercation with an assistant coach during a 41-24 loss to Oregon over the weekend.
The Fresno County District Attorney's office has filed charges against Fresno State QB Zack Greenlee and a teammate after both were arrested last month during a house party near the campus.