The Dallas Mavericks Defeat the Boston Celtics 89-73 As Dirk Nowitzki Reaches the Top 20 in Career Points [VIDEO]The Dallas Mavericks Defeat the Boston Celtics 89-73 As Dirk Nowitzki Reaches the Top 20 in Career Points [VIDEO]Dirk Nowitzki had 26 points to lead the Dallas Mavericks past the depleted Boston Celtics 89-73. Tarren HubbardTarren Hubbard