The Aggie offense also struggled under the rain, gaining 195 total yards, 70 of which came on one drive. New Mexico State had just 10 first downs in the contest.
Junior quarterback Royal Gill started after being the backup the past two games and was 17 for 31 for 105 yards. Running back Justine Buries ran for just 46 yards after running for over 100 yards in three previous games.
Meanwhile, the Bulldogs were efficient for most of the night.
Kicker Clint Stitser kicked three field goals, the Bulldogs converted 8 of 15 third downs and held the ball for 35:13
The Bulldogs added three scores in the second half after leading 20-7 at halftime. A Stitser 36-yard field goal put Fresno State up 23-7 in the third quarter, then quarterback Paul Pinegar scored from a yard out early in the fourth quarter. Pinegar's score was set up by an NMSU turnover. Aggie punt returner Stevelan Harper muffed a Bulldogs punt and FSU recovered at the Aggie 14.
Fresno State added a Mathis six-yard run to close out the scoring.
The Aggies are now 0-6 overall and 0-2 in WAC play; Fresno State is 3-1 and 1-0.
Opposing teams were averaging 227.4 yards per game on the ground against NMSU entering Saturday's game.
Fresno State controlled much of the first half behind a strong running game, while NMSU struggled on offense except for one drive.
The Bulldogs led 17-0 after one quarter, outgaining NMSU 104-43 and not allowing the Aggies to cross midfield in the opening 15 minutes.
New Mexico State, which entered Saturday's contest minus-14 in the turnover category on the season, turned the ball over just 1:13 into the game when quarterback Joey Vincent was hit by linebacker Emanuel Sanchez and fumbled at NMSU's 30. Vincent entered the game on third down and ran a quarterback draw. He didn't play again the rest of the evening.
The Bulldogs took over and, four plays later, Pinegar found receiver Adam Jennings with a 20-yard scoring strike. Pinegar was 10 of 19 passing on the night.
Jennings found room between corner Shukree Shabazz and safety Eric Carrie on the pass.
On its next drive, the Bulldogs went 37 yards on six plays and went up 10-0 after a 38-yard field goal by Stitser.
The Aggies couldn't get much going on offense and the Bulldogs took advantage late in the quarter, forcing a short Aggie punt. Fresno State went 47 yards on just four plays and went up 17-0 when Pinegar hit Jaron Fairman with a 19-yard touchdown pass. New Mexico State linebacker Jimmy Cottrell had good coverage on the play, but Fairman made a one-handed catch with his left hand.
The Aggies put together their best drive of the half in the second quarter, going 70 yards on 10 plays to pull within 17-7 with 6:13 left in the half. Derek Dubois went 36 yards on an end around, Gill gained three yards on a fourth and short inside the 10 and then hit A.J. Harris with a 3-yard touchdown pass to finish the drive. It was Harris' first touchdown catch of the season.
Gill was 8 for 11 in the half for 42 yards. New Mexico State gained 70 of its 115 first-half yards on the scoring drive.
Fresno State capped the first half with a 28-yard field goal by Stitser on a drive that took up 5:49 on the clock, leaving just 15 seconds on the clock.
The Bulldogs finished with 110 yards rushing in the first half and 196 yards total.
The Aggies are back in action next Saturday at Hawaii.