San Diego State was swept for the first time this season in Mountain West Conference play, the Aztecs' three losses at UNLV dropping them into third place behind the Rebels and first-place New Mexico.
SDSU (19-20, 10-8) lost 5-2 on Sunday against the Rebels (27-12, 11-7), who won the first two games of the series by 9-8 (in 17 innings) and 4-3 scores.
On Sunday, the teams were tied 2-2 through seven innings before the Rebels scored three unearned runs in the eighth to take the game and the series.
SDSU starting pitcher Philip Walby pitched into the eight inning, allowing 11 hits and five runs (two earned) with three walks and three strikeouts. UNLV starter Kenny Oakley went the distance, allowing nine hits, two runs (one earned), with three strikeouts and three walks.
The Aztecs return home this week, meeting UC Irvine on Tuesday at 6 p.m. for a nonconference game at Tony Gwynn Stadium before playing host to Fresno State in a MWC weekend series.
Fresno State is coming off a five-game sweep of Air Force (including two games moved to Fresno after weather postponements in Colorado Springs). New Mexico swept its series at Nevada, capping the sweep with an eight-run ninth in Sunday's 15-11 win.
MOUNTAIN WEST STANDINGS
New Mexico (14-4, 24-16)
UNLV (11-7, 27-12)
San Diego State (10-8, 19-20)
Fresno State (8-10, 13-24)
Nevada (7-11, 19-20)
Air Force (4-14, 10-28)