Junior forward James Moore led the Aggies with 21 points and eight boards. Brandon Mason added 20 points, Jason Fontenet had 16 points and eight assists and Chris Jackson added 12 points and 13 rebounds. It was Jackson's first double-double of the season.
Malerick Bedden led South Alabama with 17 points.
The Aggies shot 52 percent from the floor and made 6-of-13 3-point field goals for 46 percent. NMSU was also solid from the line going 12-of-13 for the game. The Aggies held the Jags to just 41 percent shooting and 36 percent from three point land.
"I think this was probably the best game we have played all season," head coach Lou Henson said. "We shot the ball very well and our defense was solid all night. South Alabama beat one of the best teams in the league so we know we had our work cut out for us."
South Alabama had come off a 93-89 homecourt win over UL Thursday night, handing the western division favorites its first conference loss of the season. But the Aggie defense held the Jaguars in check most of the night.
"If we can hold teams to around 40 percent from the floor we have a great chance to win," Henson said. "Chris Jackson had a great night for us on the boards and Moore and Mason did a great job for us tonight. We did a good job of shutting down their best players."
NMSU started the game by making 7-of-14 from the field and 2-of-3 from behind the 3-point arc in the first 9:30 of the half to take a 16-10 lead.
South Alabama cut the lead to 20-18 with 7:54 to go, but a Brandon Mason 3-pointer at the 7:43 mark started a 12-0 run by the Aggies, giving them a 30-18 lead with 5:54 in the half.
Both team would exchange baskets over the next five minutes, but the Aggies maintained a seven-point lead with 2:50 to go. The Aggies then ended the half with a 9-2 run, capped off with a dunk by Chris Jackson at the buzzer to give the Aggies a 14-point lead going into the locker room.
Mason led the Aggies with 12 points with Jackson adding eight points and seven boards. The Aggies shot 56 percent from the field and 71 percent from behind the arc. NMSU would hold the Jags to only 36 percent from the floor.
South Alabama went on a 19-4 run early in the second half to cut the lead to 52-49 with 12:15 remaining.
A free throw by Will Morris put the Aggies up 57-51, but South Alabama put together another scoring run to cut the lead to one, 59-58. Moore the hit two free throws on the offensive end and drew a charge on the defensive end to give the Aggies the ball back. He followed that up with a dunk to give the Aggies a 63-58 with 5:34 in the game.
The Aggies extended their lead to 74-64 with 1:06 left and four free throws by Jason Fontenet and two fast break dunks by Morris and Mason put the game away.
The Aggies turned the ball over just 11 times, their second fewest of the season.
New Mexico State will stay on the road and finish their conference opening four-game road swing at Florida International Tuesday night