KEYSER, W.Va. — WVU Potomac State led 66-58 with 6:24 to play after a layup from Avion Blackwood.
Garrett responded with a 15-7 run over the next 6:20, capped off with the go-ahead layup by Kam Heathington.
After the Catamounts (7-8, 2-2 NJCAA Region 20) missed its final two shots, the Lakers (12-3, 5-1 Region 20) held on for a 73-72 win on Monday.
Carmello Myles led Garrett with 17 points, adding eight rebounds and two steals.
Nasir Coleman scored 13 points with five rebounds and five assists while Stephen Robinson recorded a double-double with 11 rebounds and 10 points.
Daniel Charlot led all scorers with 19 points for Potomac State, finishing a rebound shy of a double-double.
Damian Thompson scored 16 points with four rebounds, three assists and a steal.
Blackwood finished with 11 points and two steals.
The game featured eight ties and five lead changes.
The Catamounts begin a three-game road trip on Wednesday at 6 p.m. against Allegheny County.
The Lakers head to Howard on Wednesday at 10 a.m.