DALLAS, Texas — The moment was there for the underdog Sooners.

Brent Venables' squad took a 3-0 late in the first quarter and kept Texas' explosive offense from finding a rhythm. But missed opportunities, a lack of execution and turnovers kept Texas alive, and the Longhorns rode that momentum to a 21-3 halftime lead.

Here's a look at what's happened so far for the Sooners through the first 30 minutes:

The recipe was clear for the Sooners — lean on the defense, and chew up the clock on offense.

In the first quarter, it was executed almost perfectly.

The Sooners' defense took the field first and three players later snagged the first takeaway of the game, thanks to a Billy Bowman interception. That set the offense up at Texas' 45-yard line. The only hiccup came later in the drive when Tyler Keltner missed a 44-yard field goal.

Outside of that, the Sooners controlled the first quarter. Defensively, the Sooners held Texas to 13 yards and no first downs in the first quarter. The results of the Longhorns' three drives in the first quarter? Interception, three-and-out, three-and-out.

Things weren't pretty on offense, but it was effective. On the final drive of the quarter, the Sooners used 11 players to soak up nearly five minutes off the clock before capping it off with a 42-yard field goal from Keltner.

In the first quarter, the Sooners nearly doubled Texas in time of possession (9:53, 5:07) and out-gained them 54-13. Most importantly, they led 3-0. Unfortunately for them, that's when things fell apart.

The hits just kept coming.

With the Sooners trailing 14-3 and the Sooners reeling, the offense desperately needed a spark. Instead, Michael Hawkins was stripped on a quarterback scramble and it was recovered by Texas.

The next play? Texas scored on a 43-yard run by Quintrevion Wisner.

Somehow, it got worse. On the first play of OU's next drive, Taylor Tatum rushed for 13 yards but fumbled the ball, and it was recovered by Texas. Fortunately for the Sooners, the Longhorns were called for a holding penalty that took away a fourth-down conversion, and they missed the ensuing field goal.

Considering the Sooners' struggles offensively, the one thing they couldn't do was turn the ball over. Instead, they turned it over on back-to-back plays that allowed the the Longhorns to take control.

The recipe for success in the first quarter didn't translate to the second. The Sooners tried to keep running the clock, but the lack of first downs killed their momentum. Both of their first two drives to open the quarter spanned five plays and 17 yards while nearly taking three minutes off the clock. But the Sooners gained just two first downs combined on those first two drives.

The Longhorns took advantage, marching 10 plays for 75 yards on their opening drive of the second quarter before capitalizing on a four-play, 84 yard drive late in the quarter to take a 14-3 lead.

OU had found some rhythm in the running game, but the lack of explosiveness in the passing game has been glaring. Michael Hawkins has completed 6/10 passes for 51 yards, averaging 8.5 yards per completion. The running game has been productive enough — 4.8 yards per carry in the second quarter, 3.8 for the half — but without any threat down the field, the Longhorns have been able to key in on Hawkins and the running backs.

— Jacobe Johnson did play a handful of snaps at wide receiver in the second quarter, though he wasn't targeted.

— Tatum was made available for the game but didn't make his first appearance until the 2:21 mark of the second quarter. His only carry resulted in a fumble.

— The Sooners still have an edge in time of possession (16:05, 13:55). But the discrepancy is production is massive. The Longhorns have 235 total yards to 107 for OU, and the Sooners averaged just 3.2 yards per play.