Smith missed 13 of 17 shots from field but made up for it shooting 12 of 15 from the foul line. Nigel Ribiero added 10 points for Grambling (11-12, 7-3 Southwestern Athletic).
With Grambling leading 69-66, Smith fouled Jared Sam with five seconds left after he converted a layup to reduce Southern's deficit to a point. But Sam missed the potential and-1 chance to tie it and time ran out.
Sam's layup gave Southern a 41-32 lead with 13:32 left. Grambling later went on an 8-0 run and Jackson tied it at 45 with a dunk. The teams traded leads before Jackson made two foul shots for a 61-60 lead that Grambling never gave up. Ribeiro made two fouls shots for a 69-66 lead with 15 second left.
Sam led Southern (9-14, 5-5) with 23 points on 7-of-10 shooting from the field and 9 of 11 from the free throw line and Aaron Ray scored 14.
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Diakite becomes fourth from UVA to pursue NBA
Mamadi Diakite, the Cavs forward from Guinea who played the hero role in Virginia's Elite Eight win over Purdue, declared for the draft, joining teammates De'Andre Hunter, Ty Jerome and Kyle Guy.
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