NORMAN, Okla. -- Too many times, Romero Osby had been a part of Red River Rivalry games that didn't turn out the way he wanted.

With victory nearly in his grasp, he told teammate Sam Grooms during a late-game huddle: "We finally got these guys." And no one played a bigger role.

Osby scored a career-high 29 points, Amath M'Baye had three rim-rattling dunks among his 15 points and Oklahoma snapped a six-game losing streak in the rivalry by beating Texas 73-67 on Monday night.

Osby scored 21 of Oklahoma's 33 points during a 14½-minute chunk in the middle of the game, powering the Sooners (13-4, 4-1 Big 12) to their first win against the Longhorns since he transferred from Mississippi State. Texas had swept both meetings last season and all three in 2011 while Osby was sitting out under NCAA transfer guidelines.

Off to its worst start to conference play since 1976, Texas (8-10, 0-5) had no answer for Osby after top rebounder Jonathan Holmes left with a broken bone in his right hand with just under 7 minutes left in the first half. Osby checked back into the game about 3 minutes later and took over.

"I attacked them once and I got an easy bucket, so I just started trying to be more aggressive," Osby said. "Just from then on, I just tried to be aggressive."

Osby went 9 for 15 from the field, 10 for 11 from the foul line and also chipped in eight rebounds, three steals and two blocks.

"We really believe that Osby is one of best players in the league," Texas coach Rick Barnes said. "We told our team that this is a guy that we think can score in a lot of different way. We just love the way he plays. He just plays within himself."

The Longhorns' game plan had been to try and attack Osby and M'Baye on the offensive end, perhaps getting them in foul trouble or at least wearing them down. That formula never really got put into action, and it went down the drain after Holmes headed to the locker room with a bag of ice on his hand.

But Barnes aimed most of his criticism at his guards for not getting the ball to the Longhorns' post players when they were open.

"Our guards have got to understand we've got to get to the foul line. We've got to put the fouls on other people," Barnes said. "We can't let especially a team that relies on their post players to score, to not have to guard."

Texas tried to mount a furious rally from an 11-point deficit in the final 1:42, after Oklahoma's student section started a "Just like football" chant to rub in an apparent victory -- to go with three straight on the gridiron.

Ioannis Papapetrou hit back-to-back 3-pointers -- the first one completing a four-point possession after Jaylen Bond split a pair of foul shots -- to get the Longhorns within 69-65 with 1:01 remaining. Sheldon McClellan then missed a 3-pointer that would have made it a one-possession game, and Osby hit a pair of free throws with 42 seconds left to cool the comeback down.

McClellan led the Longhorns with 25 points after coming off the bench for the fourth straight game. Barnes called it "one of the best games he's played just because of the way he was engaged mentally."

It still wasn't enough to keep Texas from losing its first five league games for the first time since doing it in back-to-back seasons in the Southwest Conference in 1975 and 1976 under coach Leon Black. Barnes' Longhorns had won their Big 12 opener in each of his first 12 seasons before starting out with a single loss last season.

It keeps getting worse this season with a youthful roster with no upperclassmen in the rotation, and with point guard Myck Kabongo suspended by the NCAA until mid-February.

Oklahoma, meanwhile, is off to a promising start with increasing NCAA tournament hopes.

Osby had the final nine points in an 11-2 run that put Oklahoma up 30-26 at halftime, and the Sooners started to create some distance with a string of seven straight points soon after halftime. M'Baye beat the shot-clock buzzer with a reverse layup and Buddy Hield blocked Demarcus Holland's jumper at the other end before lobbing to M'Baye for a two-handed slam.

Osby followed that by pulling up at the left wing for only his third 3-pointer of the season to extend the lead to 48-36 with 12:25 to play.

"That's not really my role on this team. We have a lot of shooters," said Osby, now 3 for 5 from 3-point range this season. "If it comes in the flow of our offense, then I'll shoot it. But if not, then I'm not worried about making 3s."

Barnes had trouble quantifying how much of a difference it made when Holmes went out, but pointed out that he was Texas' best player with the most experience.

"That's why you have a team," Barnes said. "One thing's for certain now, those young guys going to get a lot of experience. We need them to play, we need them to develop. But it still goes back to we've got to have better guard play to help those post players."