Tellinghuisen opened the game with a 3-pointer before Marshall came up with a steal and a 3 to put South Dakota State 6-0 fewer than 60 seconds in and the Jackrabbits never trailed.
Weber State (0-2) twice cut its deficit to eight in the second half, but could get no closer.
Jeremy Senglin's jumper with 14:49 left made it 53-45 but South Dakota State responded with a 10-0 run over the next three minutes and pushed its lead as high as 20, 79-59, in the final minutes.
Both teams shot at least 50 percent from the field but Weber State committed 22 turnovers, which led to 27 Jackrabbit points.
Senglin led the Wildcats with 20 points.