Jalen Moore pulled the Aggies even, 36-36 in the final minute of the first half, but Trey Kell knocked down a 3-pointer to send the Aztecs into intermission with a 39-36 advantage they maintained throughout the second half.
Shepard hit 7 of 16 from the field, hitting his lone 3-point try, grabbed six rebounds, handed out five assists and made five steals in leading San Diego State (9-6, 2-0 Mountain West). Zylan Cheatham and Kell each added 13 points.
Lew Evans was 10 of 12 from the free throw line, scored 22 points and grabbed 11 rebounds to lead Utah State (9-4, 1-1). Moore added 13 points and Chris Smith and Shane Rector contributed 12 and 11, respectively.