Graham Harrell and Texas Tech knocked OU out of the national championship chase Saturday night with a 34-27 victory.
Harrell threw for 420 yards and two touchdowns for the Red Raiders (8-4, 4-4 Big 12) and for the 11th time this season a top-five team lost to an unranked team.
Bradford, the nation's leading passer, came out with an apparent concussion with the Sooners up 7-3 after their second possession of the game.
"Then we got all kinds of personal fouls and penalties, just bad football, and you can't play like that and win on the road, or even at home, " Sooners coach Bob Stoops said.
Texas Tech scored 24 straight points after Bradford went out and by the time the Sooners got anything going on offense in the fourth quarter, it was too late.
"There were huge contributions by defense, huge contributions by special teams and huge contributions by offense," Tech coach Mike Leach said. "I think it was a game won together. I thought on this day, that the Tech defense was the biggest factor in the game."
Tech fans stormed the field after the win, the second straight in Lubbock for Leach over Stoops, his former boss at OU.
"It's unbelievable," said Harrell, who completed 47 of his career-high 72 passes. "We came out and executed. Coach Leach told us if we executed we could move the ball. That's exactly what we did."
The Red Raiders had never beaten a team as highly ranked and Leach had never scored more against Stoops.
With Oregon losing on Thursday, the Sooners (9-2, 5-2 Big 12), who were fourth in the latest BCS standings, appeared to be in good shape to play for a national title if they could win out.
But just like the Ducks, the Sooners couldn't overcome an early injury to their quarterback.
Who benefits from the Sooners' slip and the Ducks' fall? Ohio State can start thinking national title again as it watches other contenders play out the rest of the season. The Buckeyes are in the clubhouse at 11-1 after beating Michigan 14-3 early Saturday. West Virginia also has fewer teams to jump over, too.
Stoops said he didn't know how serious the injury is to Bradford, who appeared to get hurt trying to make a tackle after a turnover.
"I'm not sure whether it was a trainer or one of the players who said, 'Wait a second, he's not where he needs to be," Stoops said. "That's when they grabbed him and looked at him."
Backup Joey Halzle, who had attempted just nine passes coming into the game, struggled to lead the Sooners. He went 21-for-41 for 291 yards. He threw for two touchdowns and had one interception.
"You can't play these guys one-handed," Stoops said. "Your backup never has the number of snaps the other guy has. But Joey (Halzle) did a good job in that regard of hanging in there and continuing to play."
Oklahoma offense came up feeble on all fronts, falling short of its season averages in rushing and scoring. OU came in averaging 191 yards rushing and 45 points, but scored only two offensive TDs, the defense got another, and ran for 106 yards.
The loss put OU in a tie with No. 12 Texas for the Big 12 South title, but the Sooners can still clinch a spot in the conference championship game with a victory next week against Oklahoma State.
If the Sooners can get back to the title game, they'll face the winner of Kansas-Missouri. Who would've guessed the unbeaten Jayhawks and Tigers (10-1) would be the last two Big 12 teams in the national title race?
The Sooners scored two fourth-quarter touchdowns to make it 34-27, but Texas Tech recovered an onside kick with less than half a minute left and the upset was complete.
"The difference in the first half and the second is the offense is moving the ball some," Stoops said. "We didn't play well in the first half as a team. The second half we did better."
Harrell rushed for Tech's first touchdown. On the play before he scored, Harrell completed a 60-yard pass to his favorite receiver, Michael Crabtree. That pass allowed him to join five other quarterbacks -- two from Tech -- who've thrown for at least 5,000 yards in a season.
Tech broke it open in the second and third quarters. Harrell hit Crabtree early in the second quarter on a 13-yard TD to put Tech up 20-7. Three minutes later, Harrell hit Eric Morris from 15 yards out to give the Red Raiders a 27-7 lead.
In the third quarter, Aaron Crawford gave Tech a 34-10 with a 3-yard run.
Crabtree finished with 12 catches for 154 yards. It was the redshirt freshman's 10th game of 100 yards or more.
The Sooners went up 7-0 when Lendy Holmes intercepted a pass and returned it 67 yards for a touchdown.
It was unclear when Bradford was hurt, but he took a hard hit as he tried to make a tackle after Allen Patrick fumbled on OU's first play from scrimmage. Bradford got up slowly.
Bradford sat alone on the bench until about 10 minutes remained in the first half when he walked with trainers up a ramp leading out of the stadium and stood near the top for a few minutes.
He then got on the back of a golf cart and was taken away from the stadium area.