In addition, they also gained a measure of revenge for a 16-point whipping earlier this season in Ogden.
The Wildcats (23-5, 14-2) and Grizzlies had already clinched a spot in the semifinals, scheduled for next Tuesday.
Montana (23-6, 15-1) frustrated the Wildcats with a relentless, aggressive defense. The game turned in the first half after Weber State jumped out to an early 16-10 lead.
Will Cherry sparked a 14-0 Grizzlies run, and Weber State scored only one point during a nine-minute stretch, a free throw by Damian Lillard, who finished with 19 points. The Grizzlies eventually built an 11-point advantage before taking a 34-24 lead at the half.
Cherry finished with a game-high 23 points. Meanwhile, Montana held Weber State to 30 points below its scoring average.
"We just couldn't get the shots to fall tonight," Lillard said. "I thought we had some good looks, we just didn't make them and we couldn't make up for it and get enough stops on the defensive end. They put a lot of defensive pressure on us and we couldn't knock down the shots when we needed to."
Weber State averaged 40 percent from beyond the 3-point line this season. Tuesday, the Wildcats were 1 of 10 in the first half and 3 for 26 overall.
In addition, Montana took advantage of WSU foul trouble that put posts Kyle Tresnak and Darin Mahoney on the bench in the first 20 minutes. The Grizzlies scored 12 points in the paint during the first half.
Montana 66, Weber State 51
R IN SHORT • Weber State, averaging 40 percent on its 3-point attempts, connects on only 3 of 26 attempts.