NORMAN — At 5-0, Oklahoma survived a difficult first portion of the schedule going into its off week.
The second half of the season, however, doesn't get any easier.
The Sooners still have to visit No. 24 Missouri and No. 22 Oklahoma State, as well as Texas A&M and Baylor.
Combined, those four teams are 15-2.
Missouri, OSU and Baylor appear to be tougher games now than they did before the season. And Texas A&M, just as tough.
"The South is stacked," said OU linebacker Travis Lewis. "You go from A&M to Oklahoma State. Those teams jump out at me. Even Baylor. Baylor is playing some great football.
"It's not just a two-horse race anymore. Used to be if we beat Texas, Texas beat us, that team was in the Big 12 Championship. It's not going to be like that anymore."
The Oklahoman breaks down the second half of OU's schedule, examining what we thought we knew before the season about each Sooner opponent, and what we know now:
Oct. 16 vs. Iowa State
What we thought before the season: The Cyclones were an improved program but still destined to battle Colorado for last in the North.
What we know now: The Cyclones are even more improved, coming off an impressive 52-38 win over Texas Tech. Iowa State now seems to have a great chance of finishing no worse than fourth in the North. The Cyclones pose little threat to the Sooners in Norman, but they will be a tougher out than initially projected.
Key player: Returning from an injury to his non-throwing shoulder, senior QB Austen Arnaud unleashed the best performance of his career, throwing for four touchdowns with no picks in the win over Tech.
Oct. 23 at Missouri
What we thought before the season: With QB Blaine Gabbert, the Big 12's top returning passer, flanked by veteran running back Derrick Washington, Missouri figured to be the biggest threat to Nebraska's claim to the North championship.
What we know now: Washington has been booted off the team and Gabbert has struggled (eighth in Big 12 in passing efficiency), but Missouri is 4-0. If the Tigers get by Texas A&M in two weeks, they'll probably be undefeated when OU visits Columbia. This game looks every bit as difficult for the Sooners as it did before the season.
Key players: Since Washington's removal, the Tigers have relied on a running back platoon comprising Kendial Lawrence, Henry Josey and De'Vion Moore, among others. Whoever it uses, Missouri needs to sustain a running game to take pressure off Gabbert.
Oct. 30 vs. Colorado
What we thought before the season: With several starters back offensively, Colorado had a chance to go to its second bowl game under Dan Hawkins.
What we know now: Thanks to a big home victory over reeling Georgia last week, Colorado's bowl-game hopes remain intact despite an embarrassing 45-point loss at Cal. Games against Texas Tech and Kansas look particularly winnable, which would put the Buffs one game away from being bowl eligible. Winning in Norman, however, is still a long shot.
Key player: Junior RB Rodney Stewart has been phenomenal of late, rushing for 255 yards and three TDs in wins over Hawaii and Georgia.
Nov. 6 at Texas A&M
What we thought before the season: With the preseason Big 12 Offensive Player of the Year, QB Jerrod Johnson, the Aggies had a legit shot at the South division crown for the first time in more than a decade.
What we know now: These Aggies are not contenders. Johnson has thrown eight picks in the last two games, and A&M was fortunate it didn't lose to Florida International in addition to Oklahoma State. The chance is still there for a solid season, and A&M will have plenty to play for when OU travels to College Station in what figures to be OU's second-toughest remaining obstacle to an undefeated regular season.
Key player: After leading the Big 12 in sacks last season, defensive end Von Miller has been neutralized this year, held without a sack. For A&M to bounce back from its loss to OSU, Miller has to become more disruptive.
Nov. 13 vs. Texas Tech
What we thought before the season: The Red Raiders, probably in for some transition pains with the coaching switch from Mike Leach to Tommy Tuberville, still had enough talent to win eight-plus games.
What we know now: Talk about transition pains. After a two-touchdown loss to Iowa State, the Red Raiders face a crossroads game against red-hot Baylor this week in the Cotton Bowl. Lose there, and just becoming bowl eligible will be an uphill climb. Revenge from last year's Lubbock debacle is there for OU's taking.
Key player: With porous defense, QB Taylor Potts is going to have to carry this team. One of the bright spots so far is Potts, who has 13 TDs to just three INTs.
Nov. 20 at Baylor
What we thought before the season: Even with the return of QB Robert Griffin, the Bears seemed destined for another finish in the South basement.
What we know now: We'll know more after Saturday. If the Bears can knock off Tech, they'll be one game away from bowl eligibility. With his play so far, Griffin is vying for All-Big 12 honors, and OU's trip to Waco seems far more daunting.
Key player: As Griffin goes, so goes Baylor. That's been a good thing so far. Griffin has thrown for 1,351 yards and rushed for another 221, totaling 15 TDs.
Nov. 27 at Oklahoma State
What we thought before the season: With a new offense and a new QB, OSU could be in rebuilding mode.
What we know now: With a new offense and a new QB, OSU is third nationally in total offense. So much for rebuilding. Brandon Weeden has played as well as any QB in the league, and running back Kendall Hunter looks like his old self. We'll know a lot more about OSU after a home showdown with seventh-ranked Nebraska in two-and-a-half weeks, but as of now, Bedlam on Thanksgiving Weekend appears to be the most difficult game left on OU's schedule.
Key player: Wide receiver Justin Blackmon's development as a No. 1 receiver has been instrumental, but for OSU's offense to continue humming, he'll need to keep it up against the more talented defenses the Pokes are about to face.