SB Nation's Rock M Nation discusses the importance of getting out in front of Oklahoma early:
Who wins the first 15 minutes?
Oklahoma is quite possibly the best team in the country in the first quarter. They have outscored opponents, 73-20, in the opening 15 minutes, and their advanced stats play out in a similar fashion -- they rank second in Offensive Q1 S&P+ and 23rd in Defensive Q1 S&P+. Even in the games that ended up close, they built up a big lead almost every time.
Mizzou, meanwhile, is solid out of the gates (56-10 scoring margin, 15th on offense), but the defense takes a little while to get rolling. Mizzou ranks 60th in Q1 Defensive S&P+, meaning OU's biggest advantage will unfold at the start. If Mizzou is tied or ahead as the second quarter begins, they have dodged a major bullet. Mizzou's defense gets better as the game advances, but "getting better" won't mean as much if they give up two touchdown drives to start the game.