So which are the REAL top five defensive units, and in what order? The Dash reveals:
Alabama (12). The Crimson Tide are No. 2, but have played opposing offenses that rank a respectable 64th. Biggest achievement to date: shutting down Arkansas (No. 15 offense in the nation).
Texas. The No. 4 overall defense has bottled up offenses that rank 61st. Biggest achievement to date: holding the No. 2 offense in America, Texas Tech, to three points in the first half and 24 overall.
Florida (13). Nobody is giving up fewer than the Gators' 203 yards per game, but they've faced only one offense ranked better than 50th -- that's No. 48 Tennessee. Biggest achievement to date: zero points allowed in the second halves of two SEC road games.
Ohio State (14). The 11th-ranked Buckeyes D is allowing 272 yards per game despite having faced the best offenses of the defensive top 15, including one in the top 10 (Toledo) and another in the top 30 (Wisconsin). Biggest achievement to date: nine straight quarters of shutout football against Toledo, Illinois and Indiana.
USC (15). The No. 6-ranked Trojans defense has not been tested by anything like what it'll see from Notre Dame on Saturday, having faced just one offense in the top 70 (No. 49 California). Biggest achievement to date: just 26 points allowed after the first quarter this season.