The 10th-seeded Sooners won the first 20 minutes, but as has been the case for most of the games down the stretch, they couldn't sustain it for a full 40 minutes and fell 70-55 Friday evening to the No. 7 San Diego State Aztecs.
Locked up at 48, the Aztecs surged on an 8-0 run midway through the second half to seize control and never trailed again.
Forward Romero Osby, who finished with a game-high 22 points in his final collegiate game, hit in one of his two triples to end the run and bring OU back within five, but that's when SDSU used another 7-0 spurt to really put it away.
After the Aztecs pushed it to double figures, the Sooners never drew back within single digits again.
In the first half, it was quite a different story.
OU delivered the first punch, racing on a 12-0 burst to build an early 23-14 advantage 10 minutes in.
Shortly after, though, veteran guard Steven Pledger picked up his second foul and was one of a couple Sooners that battled foul trouble and changed things as the contest headed toward intermission.
The Sooners limped into the locker room with a 33-31 lead, but SDSU had all the momentum.
They gave up the lead three minutes into the second frame and had it again.
While Osby led all scorers, he didn't have much help with no others in double figures.
The Aztecs outshot the Sooners 42.9 percent to 39.7 percent and won the rebounding battle 40-29 after trailing by two in that category at the half.
OU ends the season 20-12, having earned its first NCAA Tournament appearance since 2009, while SDSU marches on to face No. 15 seed Florida Gulf Coast Sunday.