MANILA, Philippines — National University held off University of the Philippines, 72-64, at the Mall of Asia Arena Saturday to claim its second straight win in the UAAP Season 89 men's basketball tournament.   The Bulldogs barked to a 21-4 start and did just enough down the stretch to deny any uprising by the Fighting Maroons. Reinhard Jumamoy logged 14 points, five rebounds, and five assists for NU which improved to 2-1 and dragged UP to the same record. NU, UP, and Ateneo now share the lead in the team standings. Mac Alfanta came through with 13 points as Paul Franciso and Mo Diassana chipped in 11 and 10 markers, respectively. Arvie Poyos paced UP with 13 points, four assists, and three steals.