Norman, Okla. ? Ivan McFarlin scored on putbacks, soft jumpers in the lane and even a few dunks on the break.

The Oklahoma State forward almost didn’t miss, and Oklahoma couldn’t counter with much offense of its own.

McFarlin was 10-for-12 from the field and scored 21 points, leading No. 7 Oklahoma State to its first Bedlam Series season sweep with Oklahoma in six years with a 65-52 victory Monday night.

“My shots were just falling,” McFarlin said. “I was there at the right time to put the buckets in.”

The Cowboys (20-2, 10-1 Big 12 Conference) have won 10 straight games and remained on track to secure their first outright conference title since winning the then-Big Eight in 1965. Oklahoma State extended its first-place lead in the league to 11/2 games over Texas.

The Sooners (16-6, 6-5) lost at home for only the third time in 51 games.

Oklahoma State finally started to pull away from its offensively challenged rival after an 8-0 run that was capped by Tony Allen’s thunderous one-handed dunk, giving the Cowboys a 37-29 lead with 15:50 to play.

The Sooners, meanwhile, made only one of their first 17 shots in the second half and went more than nine minutes without a basket until Jason Detrick scored on a breakaway layup with 9:20 left.

By that point, it was too late for Oklahoma to mount much of a challenge to the surging Cowboys.

Oklahoma State guard Tony Allen puts up a shot against Oklahoma forward Johnnie Gilbert (32) during their Big 12 Conference game. The Cowboys cruised to win their Bedlam Series game, 65-52, Monday in Norman, Okla.

“The first four minutes of the second half were crucial,” Oklahoma coach Kelvin Sampson said. “We had a lot of good looks. You just have to make shots.”

McFarlin had consecutive baskets that gave Oklahoma State a 15-point lead with 4:38 to play.

His last field goal started the exodus of Oklahoma fans out of Lloyd Noble Center.

McFarlin, a fourth-year junior, only missed his final shots of both halves.

“After the game was over, I went in the locker room and just put my head down and began to have a little tear roll out,” said McFarlin, who tied a season high in points. “This is a big step in my OSU career, just sweeping them.”

In a nod to the Sooners’ offensive ineptitude, the crowd’s biggest cheers came for freshman forward Larry Turner, who made two free throws after missing four straight earlier.

Oklahoma, the worst-shooting team in the Big 12, went 6-of-30 (20 percent) in the second half after leading 27-26 at halftime.

The Sooners hadn’t shot so badly at home since a 72-57 loss to Cincinnati on Dec. 12, 1999.

By the end of the game, Oklahoma State’s fans had drowned out the crimson-clad crowd with chants of “Go Cowboys Go!”

Oklahoma State hadn’t swept the “Bedlam” series against Oklahoma since 1998. The Cowboys started their winning streak with a 77-56 victory over the Sooners last month.

John Lucas scored 18 points for the Cowboys and Joey Graham added 13. Allen, the team’s leading scorer, had six points.

Jabahri Brown led Oklahoma with 16 points. De’Angelo Alexander and Jason Detrick each had 11.

“It’s real frustrating. The guys started to get down instead of keeping our poise,” Alexander said. “We have some parts missing that we’d like to have in there, but we’re way better offensively than we played.”

Drew Lavender, who scored 31 points against Texas A&M on Saturday in the top scoring performance by an Oklahoma freshman in 20 years, was clearly overwhelmed in his matchup against Lucas.

Lavender had only one assist and five points on 2-of-9 shooting. He also fouled out with 3:29 left.

“I don’t think tonight he got into the right start offensively,” Lucas said. “He hit a big-time 3 in my face but I just made sure I stayed in his face and tried to contain him.”

Oklahoma had better solve its offensive problems quickly: On Saturday, the Sooners host No. 11 Texas, a team that held them to their lowest scoring output in nearly 50 years in a 66-37 loss on Feb. 8.