Xavier Thames had 15 points and seven assists as the Aztecs won easily in their Mountain West Conference tournament opener over the Aggies in Las Vegas.

Winston Shepard added 13 points for San Diego State (28-3), which shot 52.5 percent from the field, including 7-of-17 from 3-point range. The win moved the top-seeded Aztecs into Friday semifinals against UNLV.

Jarred Shaw led the way for eighth-seeded Utah State (18-13) with 14 points. Spencer Butterfield, who came into the game averaging 13.3 points, was held to two on 1-of-6 shooting from the field.

The Aztecs started hot, hitting nine of their first 18 field-goal attempts to open up an early 20-8 lead. The lead was 11 when San Diego State went on a 9-0 run over a two-minute span to push the advantage to 20 before going up by 21 at halftime.

Things didn't get better for the Aggies in the second half, as the Aztecs opened with a 6-0 run to push their advantage to 27. The lead reached 31 on Josh Davis' jumper with just under 14 minutes to play, and the rout was on, with coach Steve Fisher able to clear his bench and rest some starters for the semifinals.

GAME NOTEBOOK: The 39 points scored by the Aggies was their worst offensive showing of the year, eclipsing the 42 they scored the previous time they played at the Thomas & Mack Center against UNLV on Jan. 22. … The Aztecs won the rebound battle 35-27 behind a game-high 13 boards by Josh Davis, who also recorded six steals. … San Diego State won despite shooting just seven free throws, its fewest in a win this season, which topped the nine attempted in its last meeting with Utah State.