The Demons outscored the Cardinals 27-2 in points off turnovers, snagging 12 steals as Lamar suffered 20 turnovers. Northwestern made only 10 while getting balanced offensive production led by 15 points a piece from Shamir Davis and DeQuan Hicks, with O.J. Evans adding a season-best 10.
It was the third straight win for the Demons (8-4 overall, 2-0 in the Southland) in their fourth game in seven days. They play three more next week, all conference games on the road. Lamar dipped to 2-12 overall and 0-2 in league play after its 13th road game of the season.
Stan Brown (13 points, a game-high 14 rebounds) and D.J. Muepo (13 points, eight rebounds, five assists) led Lamar, with Amos Wilson scoring 12 and Donnel Minton 10. The Cardinals shot only 34 percent from the field and made just half of their 20 free throws while failing to make any of their three 3-point tries.
West ranks 38th nationally in steals and raised his season's average from 2.3 to 2.7 Saturday in just 20 minutes.
The Demons never trailed and held the Cardinals without a basket for almost seven minutes while moving up 23-13. A 10-2 run that ended the half, punctuated by a buzzer-beating Davis 3-pointer on a nice feed by West (who had five assists), moved NSU ahead 48-27 at the game's midpoint.
Lamar fought back within 52-42 with 13:04 to go, scoring nine straight points, but Hicks had two baskets in an 8-0 burst over 90 seconds to make it 60-42.
"We started attacking and making basketball plays," said 14th-year Demons coach Mike McConathy. "Lamar did a good job of offensive rebounding to get back into the game, but we were able to stop their run and get it back in our favor. We locked down, turned it up a notch defensively and did a nice job to take control."
Northwestern put it away with a burst of 13 straight points in a 3:20-long span, with West making three steals that produced baskets and Hicks scoring six points and adding a steal as the Demons soared ahead 80-50 with 4:38 remaining.
The lead was as large as 31 in the closing minutes while McConathy cleared the bench and slowed down the offense, working the shot clock down under 10 seconds before attacking the basket. Sixteen players got on the floor for NSU, with 11 scoring, as the Demons overcame 39 percent shooting aim by making 25 of 35 (71 percent) on free throws, including 9 of 12 by Davis.
NSU, the nation's second-highest scoring team, topped its 84.6 average on an Evans dunk with 2:36 to go.
Northwestern plays on the road three times next week: Monday night at Sam Houston State, Thursday night at Oral Roberts and Saturday afternoon at Central Arkansas. The next home game is Thursday, Jan. 17 against Nicholls.