COLLEGE STATION -- For the first half Saturday, No. 8 Texas A&M looked like a team that could move to the Southeastern Conference and thrive, if not dominate.
But everything changed during a nightmarish third quarter, when the Aggies turned in a 15-minute stretch that wouldn't hold up against an also-ran from the Southland Conference.
It certainly did not work against No. 7 Oklahoma State, which erased a 17-point halftime deficit with a third-quarter flurry aided by three Aggies turnovers during the Cowboys' 30-29 victory at Kyle Field.
The stunning numbers: OSU, which managed only a first-half field goal, racked up 275 yards and three touchdowns on 37 offensive snaps in the third quarter. A&M countered with 59 offensive yards, two interceptions, one lost fumble and zero points.
Sign Up and Save
Get six months of free digital access to the Star-Telegram
Mix in a squandered 20-3 lead and a wasted opportunity to announce the Aggies' presence as a major player in the BCS national title race and you've got a recipe for an angry, disappointed locker room.
That proved to be the prevailing sentiment among the guys in maroon after the Aggies (2-1, 0-1) dropped a pivotal Big 12 opener to the Cowboys (4-0, 1-0) on a day when OSU quarterback Brandon Weeden threw for a school-record 438 yards and two touchdowns.
"I hope they're [angry] about the way they played because I'm [angry] about the way I coached," said defensive coordinator Tim DeRuyter, who watched the Cowboys' up-tempo offense wear down A&M by running 58 plays -- covering 299 yards -- during a 27-point surge in the second half on a 91-degree day.
At least three A&M defenders, including safety Trent Hunter, battled cramping issues during OSU's rally. Cornerback Coryell Judie, the team's top cover man, never took the field because of a hamstring ailment that surfaced this week. But Hunter, a senior team captain, said none of the missing players mattered as much as a missing intangible: passion.
"We gave the game away," Hunter said, citing a "lull in the third quarter" for the second consecutive season in a matchup against OSU, which won last year's contest with a 38-35 comeback in Stillwater, Okla. "We didn't go out in the second half and win. We didn't step up... That's disappointing."
In addition to four turnovers and various assignment errors, A&M coach Mike Sherman cited a pair of "stupid penalties" that prolonged OSU scoring drives: a late hit on linebacker Jonathan Stewart during OSU's second touchdown march of the third quarter, and defensive end Damontre Moore's unnecessary roughness penalty (away from the play) that converted a third down on the Cowboys' drive to stretch a fourth-quarter lead to 30-20.
"Some of those stupid penalties... we should've been off the field," Hunter said. "It's uncalled for. We can't have guys on our team that are going to make penalties like that."
Both Sherman and Hunter said the penalties would be addressed in upcoming meetings. What cannot be corrected is the damage A&M did to its national title hopes, which were on the rise as the Aggies rolled up 301 offensive yards (7.5 per play) while sprinting to a 20-3 halftime lead.
But those hopes hit the wall with a thud in the fourth quarter, when OSU fans serenaded the soon-to-be SEC-bound Aggies with chants of "Big 12! Big 12! Big 12!" down the stretch.
"We had so much on the line coming into this game. This one especially hurts," said quarterback Ryan Tannehill, who threw three interceptions, including one that ended the Aggies' final drive with 1:31 remaining. "We had such high expectations coming into this year."
A&M's Big 12 title hopes took a hit by losing to a fellow contender that passed its toughest road test of the season in front of 87,358, the fourth-largest crowd in stadium history.
Weeden called Saturday's triumph "my biggest win" as OSU's starting quarterback.
"These opportunities don't come around very often," Sherman said. "You've got to grab hold when you can."
Saturday, A&M could not.
Follow Jimmy Burch on Twitter @Jimmy_Burch.
Jimmy Burch, 817-390-7760