Updated

Oklahoma had plenty of help from penalties to take a lead that looked like a baseball score against the potent Baylor offense.

The undoing for the No. 12 Sooners came on a couple of their own mistakes.

Bryce Petty threw for three touchdowns and ran for two more, including one after an offside penalty that led to a 93-yard drive, and the fifth-ranked Bears stayed undefeated by passing their first big test with a 41-12 victory Thursday night.

Oklahoma had a 5-3 lead on a safety and field goal in the second quarter and was down just 10-5 when it forced a third-down incompletion inside the Baylor 10.

But Sooners linebacker Erik Striker ran across the line of scrimmage trying to get a head start on a blitz, the Bears got a first down on the next play and Petty finished the nine-play march with a quarterback sneak.

"We have them stopped, backed up ... and we're offside," Sooners coach Bob Stoops said. "So they get another shot at it, make it, they end up scoring a touchdown.

"We didn't play smart."

Blake Bell just about ruined the Sooners with his biggest mistake on the next play — an interception thrown right into the arms of linebacker Eddie Lackey at the Oklahoma 38.

Petty ran 14 yards on third-and-10 before a double-pump throw to Antwan Goodley, whose Big 12-leading ninth TD catch was a spectacular grab with both arms fully extended. He held on for a 24-yard play that gave the Bears two scores in the final minute of the first half for a 24-5 lead.

Oklahoma (7-2, 4-2) has a 21-2 lead in the series, but both losses have come in its last two trips to Floyd Casey Stadium for prime-time games.

"It chipped away at our team's performance," Stoops said of an offense that had just 98 yards at halftime. "In the end you have to stay on the field. You're not going to go out there and keep putting your defense out against Baylor and continue to give them opportunities and not have it affect you."

Baylor (8-0, 5-0 Big 12) stretched its school-record winning streak to 12 games since a loss at Oklahoma last November. The Bears are 8-0 for the first time and 5-0 at home against Top 25 teams since the start of the 2011 season.

Even though Baylor came in leading the nation in scoring (64 points per game) and total offense (718 yards per game) — and was outscoring opponents by an average margin of 48 points — many questioned how good the Bears were after getting into November without playing a ranked opponent. They have now, and they responded with an impressive victory against a team that used to routinely overwhelm them.

"We're just talented, man. We're committed. I think that's all you can say about it," said Petty, who completed 13 of 26 passes for a season-low 204 yards and ran 16 times for 45 yards. "It's a very special team."

Baylor running backs Lache Seastrunk and Glasco Martin got banged up in the game, so Shock Linwood ran 23 times for 182 yards.

The Bears also were missing top receiver Tevin Reese, who was without a catch before dislocating his right wrist. He spent the second half on the sideline with his arm in a sling, and coach Art Briles said afterward he hopes Reese can be back for a bowl game.

Baylor got penalized 38 yards on one play late in the first quarter, including a targeting penalty and two flags for unsportsmanlike conduct, setting up Oklahoma at the 7.

The Sooners failed to score when Bell was tackled for a 1-yard loss on fourth-and-goal from the 1 by cornerback K.J. Morton, who had been called for targeting only a few plays earlier.

Morton was flagged after a vicious hit on Sterling Shepard that knocked the ball loose and laid out the receiver. Officials reviewed the play and determined it was a shoulder-to-shoulder hit, overturning Morton's ejection and keeping him in the game. But the penalty still stood, and there was extra yardage tacked on for the calls against cornerback Ahmad Dixon for unnecessary roughness and then taking his helmet off while on the field.

Two plays after Bell was stopped on fourth down, Petty was sacked in the end zone by Dominique Alexander for a safety. Jalen Saunders then returned the free kick 55 yards to the Baylor 12, though the Sooners had to settle for Michael Hunnicutt's 22-yard field goal.

"It's frustrating," said quarterback Trevor Knight, who subbed for Bell several times and had five carries for 17 yards but didn't throw a pass. "As an offensive player, especially a quarterback in this league, you want to be able to go out there and just light it up. And every time you don't, it's kind of a damper on you."

Oklahoma finally got in the end zone when Bell threw a 10-yard TD pass to Roy Finch on fourth-and-3 with 3:20 left in the third quarter.

Bell finished 15-of-35 passing for 150 yards with a touchdown and two interceptions. Oklahoma had 237 total yards.