Lujan completed 25 of 43 passes, tying the school's second-most passing yards in a game. Brandon Anderson hauled in a 13-yard touchdown pass from Lujan, who threw 10- and 29-yard scoring throws to Jake Wieneke for South Dakota State (3-0).
Wieneke finished with seven catches for 163 yards and has caught two touchdown passes in each of the Jacks' three games.
SDSU limited the Colonials (1-3) to just 26 yards in the second half before Dante Satcher broke off a 54-yard run in the closing minutes. Robert Morris ran for a quiet 228 yards. It had just 85 yards of total offense in the second half.
Nic Lamica scored the Colonials' only touchdown on a 6-yard pass from Mathew Barr. Lamica had three catches for 37 yards.
AP College Football website: www.collegefootball.ap.org