Chibuzo Agbo scored 21 points, Josh Cohen added 18 points and Southern California held off a tough effort from visiting Grambling State en route to an 80-69 Trojans win on Sunday in Los Angeles.After exchanging the lead 20 times, USC (5-1) opened up a 12-point lead midway through the second half on the strength of a 14-0 run. Agbo knocked down a pair of 3-pointers, part of a 4-of-9 shooting night from beyond the arc for him, during the surge.Grambling (1-4) responded with an 13-3 run that brought the Trojans lead back to a one-possession margin. A P.J. Eason dunk with 4:36 remaining in regulation brought the Tigers within 68-66.Desmond Claude responded with a layup on the other end, and Agbo forced a turnover on the ensuing Grambling possession to set up his own score at the rim. The four quick Trojans points gave USC a cushion it maintained down the stretch.Claude finished with 14 points, five rebounds and five assists. His swipe from Mikale Stevenson in the final minute and transition lay-in put the game away for USC, which closed its season-opening, six-game homestand with a pair of wins after last Sunday’s loss to Cal.