Gonzaga reached the championship game of the Old Spice Classic, where the Bulldogs will meet Davidson on Sunday.
The Bulldogs advanced to 5-0 for campaign, opening a 10-point halftime lead and boosting it to 20 before the midway point of the second period.
Harris was the only Gonzaga player in double figures, hitting 7-of-10 from the field. Four others had eight points each.
The Bulldogs limited Oklahoma (3-1) to 32 percent from the field. Romero Osby led the Sooners with 13 points.
Davidson reached the tournament's title game with a 63-60 win over West Virginia.