San Diego State scored eight straight points before Osby could slow them with a 3-pointer. Thirty seconds later, San Diego answered back with a three. The Sooners missed seven straight shots until M'Baye scored a basket.
Last week against Iowa State, no Sooner made a basket with about eight minutes remaining. In the last nine-plus minutes against San Diego, Oklahoma scored just seven points.
The Sooners shot 37 percent in the second half and missed 16 of 21 3-point attempts.
Osby finished with 22 points. No other Sooner hit double digits in scoring.
Jamaal Franklin led San Diego State (23-10) with 21 points.
Pledger, who OU coach Lon Kruger said the Sooners needed making shots, was 1-of-8 and finished with three points. Shots that he had been making all season were no longer falling.
“It wasn't the way I wanted to go out,” Pledger said, his eyes red with tears.