No. 5 Oklahoma must win three straight games against Top 10 opponents to win a national title.

The potential three-game gauntlet begins at 11 a.m. Saturday as the Sooners try to defend their Big 12 title in a rematch with No. 9 Texas in AT&T Stadium (home of the Dallas Cowboys) in the Big 12 Championship.

Oklahoma played their way in with a 59-56 victory at No. 15 West Virginia last Friday night. Texas struggled to get a spot in the playoff with a 27-17 win at Kansas.

Texas won the first game between the two teams in October, 48-45, with a last second field goal. The two teams have never played twice in one season in their storied history. OU was a 7-point favorite Monday to beat Texas and capture their fourth Big 12 Championship in a row.

Here is how the Sooners could reach the national championship game.

First, beat Texas.

If No. 1 Alabama beats No. 4 Georgia in the Southeastern Conference championship Saturday, the Crimson Tide would lock up the No. 1 seed in the playoff. If Georgia wins, the playoff committee would have a difficult decision. Georgia would be the conference champion and yet Alabama was undefeated in the regular season.

If No. 2 Clemson defeats Pittsburgh in the Atlantic Coast Championship, Clemson would lock up the No. 2 seed. If Pitt wins, that would knock Clemson out of the playoff.

No. 3 Notre Dame (12-0) finished their regular season with a win over 5-7 Southern California and would appear to be a lock for the playoff.

Most likely, No. 5 would be the fourth pick in most scenarios. The wild card would be No. 6 Ohio State, who plays No. 21 Northwestern in the Big Ten title game Saturday.  The committee could decide to jump the Buckeyes over the Sooners but that seems unlikely since OU has been ranked higher than Ohio State. And should OU beat Texas, the Sooners would have beaten every team on their schedule. And the committee would have to weigh a 3-point loss on a neutral site to No. 9 Texas versus Ohio State’s 29-point loss to unranked Purdue.

Here’s another problem. If Georgia beats Alabama and the committee decides to put both in the playoff with Notre Dame and Clemson, that means that the champions of three major conferences – the Big 12, the Big Ten and the Pacific 12 – will be shut out while SEC has two representatives.

That wouldn’t sit well with a lot of college football fans across the nation. Last season, the SEC had Georgia and Alabama plus Clemson from the ACC and OU from the Big 12.

ESPN.com projects OU as playing Alabama in the first round of the playoff.

OU made a strong case with the 59-56 win at then-No. 7 West Virginia Friday night.

Heisman candidate Kyler Murray of Oklahoma hit 20 of 27 passing for 364 yards and three touchdowns.  Murray rushed nine times for 114 yards and a touchdown. Murray accounted for four touchdowns in the game (three passing, one rushing).

“He’s awesome,” OU coach Lincoln Riley said of Murray. “Big moment, big atmosphere. He had the fumble, and he had the interception. It was actually a good read. It should’ve been a touchdown. I think we gave up a little pressure, and he wasn’t able to get into the throw. But his mind was sharp all night. West Virginia did some things that they hadn’t shown, and he just processed it all like he has all year. It was just a special, special performance by him.”

OU wide receiver Marquise Brown had 243 receiving yards – second most in OU history – and two touchdowns on 11 receptions (22.1 average). Last year, Brown had a career-high 265 vs. Oklahoma State. Brown scored receiving touchdowns of 25 and 45 yards, and now has 10 receiving TDs this season and 17 in his career. His 65-yard reception in the second quarter was his seventh reception of at least 50 yards this season.

“(Number) 1 (redshirt junior quarterback Kyler Murray) and (number) 5 (junior wide receiver Marquise Brown) are the quickest kids I’ve ever seen, ever,” said West Virginia coach Dana Holgorsen. “Quickest, fastest kids. They’re special players, special talents. I didn’t think they could top, offensively, what they did last year, but they’re pretty good.”

OU running back Kennedy Brooks rushed for a career-high 182 yards and a touchdown on 21 carries (8.7 average). Brooks has rushed for at least 165 yards in each of the last three games.

Texas will present a challenge Saturday. The game is at a “neutral site” but it is in Texas and unlike the regularly scheduled game, chances are there will be a lot more Texas fans in attendance.

Texas quarterback Sam Ehlinger has a sore shoulder and has passed for less than 155 yards in his last two games. But OU’s defense has surrendered more than 40 points in the last four games. But they were all victories – the first time OU has allowed 40 or more points in a single season in history.

After the Texas loss, OU fired defensive coordinator Mike Stoops and shuffled their defensive personnel. Cornerback Tre Brown replaced Parnell Motley and strongside linebacker Caleb Kelly took over for Mark Jackson, Jr.

“There’s a lot of history on the line, things that are meaningful for us because the history of our program is important to us,” Lincoln Riley said. “When you have a chance to make history around here, you’re doing something pretty special. Can’t wait to get back there.”

OU has a better offense than Texas and Texas has a slightly better defense. OU has better special teams’ play.

OU kicker Austin Seibert moved into third place in NCAA career scoring among kickers. He scored 11 points against West Virginia and now has 476 career points. Seibert hit a 37-yard field goal in the third quarter and now is 12 of 14 on field goals this season, including 12 for 12 in Big 12 play.