King and Mitchell-Cole combined for 5-of-19 from the field and 4-of-8 from 3-point range for UTSA, who now sits a 2-2 on the season. NSU (2-1) fell for the first time.
Janelle Perez led the Lady Demons, who shot 38-percent (21-55) from the field and 21-percent (3-14), with nine points. She had two assists and four turnovers.
Trudy Armstead and Chelsea Rogers each scored eight, and Rogers had nine rebounds.
UTSA forced NSU into 14 turnovers and had four steals. NSU forced 13 turnovers and had three steals.
The Roadrunners were 23-of-62 from the field and 6-of-18 from behind the arc.
Northwestern State was down 35-21 at halftime, but came back in the second half to outscore the Roadrunners by one (28-27).