In a back-and-forth second half, Denver (3-4) tied the game at 55-all on Bobbitt's jumper with 2:12 left, then both teams went cold over the next two minutes before Rosga made the winning basket. Weber State's Jeremy Senglin missed a 3-pointer at the other end with eight seconds left and Denver got the rebound to seal the win.
Weber State got 15 points from Senglin. Kyndahl Hill added 14 points and 12 rebounds.
Adapting to life on the perimeter without Nigel Williams-Goss and Jordan Mathews will be a significant test this season for No. 17 Gonzaga.
Ahmad Caver had 22 points and six assists to lead Old Dominion to a 62-44 victory over Indiana State at the Charleston Classic on Friday.
Ria'n Holland scored 13 points, Jordan Strawberry had nine points, a career-high 13 rebounds and seven assists, and Mercer beat Liberty 63-48 on Friday in the first game of the relocated Paradise Jam.