No. 5 Auburn vs. No. 6 LSU: Positioning in the SEC West and the national championship picture is at stake. The winner remains solidly in the BCS mix, but the loser will need significant help. This is the best defense Auburn QB Cam Newton, right, will have faced. Winning guarantees little in the West, since both teams still must face No. 7 Alabama.
Big 12 —No. 3 Oklahoma at No. 18 Missouri: Oklahoma leads the Big 12 South and is No. 1 in the BCS, while Missouri leads the Big 12 North. The Sooners pummeled the Tigers by a combined 100-38 in the 2007 and ’08 conference championship games. This could be a signature game for Missouri.
Mountain West —Air Force at No. 4 TCU: A true test for TCU’s defense in the last of three consecutive home games, this one against the triple-option Falcons, who are out of the top 25 after losing last week. The Frogs, No. 5 in the BCS, have won a school-record 18 in a row at home.
