Baker Mayfield throws four touchdown passes in the first half as No. 14 Oklahoma improves to 7-2 with a 34-24 victory over Iowa State. (1:26)

AMES, Iowa -- With 4 minutes, 30 seconds to play in the first half Thursday night, Iowa State set the stage for an another unexplainable upset bid at Jack Trice Stadium. Fourteen seconds later, Oklahoma's Baker Mayfield hit Dede Westbrook for a 65-yard touchdown, and the air left the building in a flash.

The No. 14 Sooners beat the Cyclones 34-24 in a tricky matchup to open Week 10 in college football, playing without two of its top weapons in running backs Samaje Perine, out for the third straight game with a leg injury, and Joe Mixon, who was suspended this week for a violation of team rules.

Junior fullback Dimitri Flowers rushed for 115 yards. Mayfield threw for 328 yards and four touchdowns as Oklahoma kept alive its bid for a perfect Big 12 season and an outside shot at the College Football Playoff.

Iowa State had won 10 of its past 13 Thursday night games, entering this contest with a strange history of weeknight happenings in Ames that dates to a two-point loss to second-ranked Oklahoma 32 years ago.

It was another productive outing for Baker Mayfield on Thursday at Iowa State, with Dede Westbrook again the Oklahoma quarterback's favorite target. AP Photo/Charlie Neibergall

So when ISU (1-8, 0-6 Big 12) scored from 41 yards on a fourth-and-2 run by quarterback Joel Lanning to go up 17-14, more weirdness appeared on tap. The Cyclones, playing without top running back Mike Warren, rotated Lanning with QB Jacob Park regularly.

It was not to be, though. The Sooners (7-2, 6-0) passed their final test in advance of a three-game closing stretch that gives them a chance to impress the playoff committee against the Big 12’s other top teams. No. 17 Baylor visits Norman on Nov. 12, followed by an OU trip to No. 20 West Virginia and then a Dec. 3 Bedlam finale at home against No. 18 Oklahoma State.

No two-loss team has qualified for the four-team playoff. And a representative from the Big 12, arguably the weakest Power 5 league of the three-year playoff era, looks unlikely to be the first.

Before this week, the top team in each of the Power 5 leagues hadn't placed lower than 11th in any of the committee’s 2014 and 2015 rankings. Oklahoma is the the committee's top-ranked Big 12 team at No. 14. Yet the Sooners, who lost in September to Houston and Ohio State, probably give the Big 12 its best shot to crack the top four. A 9-0 Big 12 record, which no team has achieved since the league instituted a round-robin schedule in 2011, would give them an important chip to play.

Even with nine straight wins to finish, Oklahoma would likely need considerable help from higher-ranked members of the other Power 5 leagues.

Westbrook, the senior wideout, continued his brilliant play Thursday with seven catches for 131 yards. The Mayfield-to-Westbrook connection with four minutes to play in the first half marked the junior quarterback’s FBS-high ninth TD throw of 65 yards or more this season.

Oklahoma then marched 75 yards as Mayfield managed the clock nicely and hit the fullback Flowers for an 11-yard TD with six seconds left in the first half to push the Oklahoma lead to 11 points.