Buddy Hield scored 39 points, Ryan Spangler made a series of critical plays down the stretch and sixth-ranked Oklahoma beat Number 21 Iowa State 79-76 Thursday night in the Big 12 Tournament quarterfinals. Georges Niang matched a career-high with 31 points for the sixth-seeded Cyclones (21-11), who trailed by 14 midway through the second half before making it a game.