O'Neale was 5 of 7 from the field, while Griffin was 3 of 5 and had four rebounds.
Southern Utah had a one point lead early in the first half, but Denver (4-6) led 40-20 at halftime and never looked back. The Pioneers shot 55 percent from the field for the game, while the Thunderbirds shot 40.8 percent.
This was the third-straight home win for the Pioneers.
Maryland point guard Melo Trimble has withdrawn from the NBA draft and will return to College Park for his junior season, sources told ESPN.
Louisville's Chinanu Onuaku, who recently underwent a medical procedure to correct a heart rhythm issue detected during the combine, will keep his name in the NBA draft pool.
Andrew White III will return to the Nebraska men's basketball team next season after removing his name from the NBA draft.