Naar led the Gaels (2-0) with 22 points, Landale added 20 and Hermanson finished with 16. They combined to make 23 of 36 shots from the field (63.9 percent).
Hermanson followed a 9-of-10 shooting performance in Saturday's season opener against St. Francis (Pa.) by making 5 of 7 shots against the Aggies (1-1).
Landale also had 10 rebounds and four assists. Naar led the Gaels with five assists. Cullen Neal contributed 12 points off the bench.
New Mexico State was led by Zach Lofton's 18 points. Eli Chuha and A.J. Harris each had 13 points. Jemerrio Jones finished with 11 points and 10 rebounds, his second consecutive double-double to start the season.
Saint Mary's, which trailed by as many as eight points in the first half, pulled away in the second half behind a 9-0 run that increased its lead to 74-59 with 8:56 remaining.
The Aggies responded after trailing 29-21 in the first half with an 11-3 spurt, tying the score at 32 with 5:52 remaining before halftime. Evan Fitzner had five points and Hermanson four in that crucial stretch for the Gaels.
A layup by Neal with 1:40 remaining in the half capped a 10-3 run by Saint Mary's, giving the Gaels a 42-38 lead.
The Gaels took a 47-42 lead into halftime. Dating to last season, they are 27-1 when leading at halftime. They are also 30-0 when shooting a better 3-point percentage than their opponents and 28-0 when outrebounding the opposition.
Saint Mary's made 50 percent of its 3-pointers compared with New Mexico's 38.1 percent. The Gaels outrebounded the Aggies 34-28.
NOTES: Saint Mary's is 126-18 (.875) at home versus non-conference opponents since 2001-02. ... Saint Mary's F Kyle Clark did not play because of a knee injury sustained in practice last week. He has missed the Gaels' first two games. His status for Wednesday's game against Cal State Fullerton is undetermined. ... New Mexico State returns home Friday to play rival New Mexico, which is coached by former Aggies coach Paul Weir. After New Mexico fired Craig Neal, the Lobos hired Weir in April. Weir was an assistant for 10 seasons at New Mexico State before replacing Marvin Menzies as head coach last season.