College Football Rankings: 5 Toughest Defenses in the Top 25

In college football, great offense is exciting, but great defense wins championships. The same will be said at the end of this season.

Oklahoma, LSU and Alabama are arguably the three best teams in the country—and it's no coincidence that these teams are riddled with talent on defense.

Defenses can be good for many reasons: stuffing the run, covering the pass, creating turnovers and giving the offense a chance to win the game. That is what every great defense does, and they do it week in and week out.

The Top 25 has several talented teams heading into Week 5. Some teams thrive with the ball in their hands; others crave opponents toting the rock in their direction.

Here are the five toughest defenses in the Top 25.

5. Wisconsin Badgers

The Wisconsin Badgers' defense was a question mark heading into the season.

Despite not facing any major competition through four weeks, the questions appear to be answered.

Led by Chris Borland and Aaron Henry, the Badgers' defense has improved as each week passes. Borland is a tackling machine, and Henry is the leader of the Badgers' secondary. Both are relied upon for leadership and playmaking.

Through the first three weeks the Badgers only had one takeaway. Last week, they registered two interceptions and appear to be hitting their comfort zone.

And the timing could not be better with Nebraska coming to town in Week 5.

Wisconsin is a blue-collar team. They work hard in the trenches and play physical pass coverage on the outside. Judging by the improvement shown already, this defense should be even better by the end of the season.

4. Virginia Tech Hokies

Virginia Tech struggled on defense last season, which is extremely rare for the Hokies.

Defensive coordinator Bud Foster seems to have fixed the problem, though.

This season, the Hokies' defense has six new starters. However, because of the inexperience and struggles of last season's defense, all of those players saw significant time.

Led by Bruce Taylor at inside linebacker, as well as dynamic cornerbacks Jayron Hosley and Rashad Carmichael, the Hokies are back and filled with playmakers who are always in attack mode.

Considering the relatively weak ACC this season the Hokies' defense may not get tested often. When they do, expect Foster's bunch to answer the bell.

3. Oklahoma Sooners

The Oklahoma Sooners are privileged to have an outstanding defense to go with their outstanding offense.

The Sooners were able to prove this by knocking off Florida State in Week 3; defensively, Oklahoma kept the Florida State attack under wraps.

They have talent on all three levels.

Frank Alexander is a dangerous pass-rusher.

Travis Lewis, Tom Wort and Tony Jefferson make one of the best linebacker trios in the nation. Jefferson was Big 12 Defensive Freshman of the Year in 2010, and Lewis is one of best defensive players in the nation.

Corey Nelson would start for anyone else.

Jamell Fleming gives the Sooners a shut-down cornerback—a very good thing to have in the offense-heavy Big 12.

The Sooners are hoping this is the year to hoist a championship trophy; much of that will depend on the success on defense.

2. LSU Tigers

If the LSU Tigers win the National Championship this season it will be on the coattails of their extraordinary defense.

The Tigers' defense is extremely athletic, and they are also very aggressive at all times.

Add in their opportunism, and you have one menacing bunch.

Tyrann Mathieu and Morris Claiborne lead the way from the secondary. Both are exceptional in coverage and have very good ball skills. They are also physical enough to body up with larger receivers; Mathieu has forced 13 turnovers in his young collegiate career.

Kevin Minter, Ryan Baker and Stefoin Francois give the Tigers a very fast trio of linebackers. All three play sideline-to-sideline.

Up front, Sam Montgomery improves every week. The sophomore appears primed to become a major pass-rusher in the SEC.

LSU may not win it all.

And if they don't, chances are fingers will not be pointed at this defense.

1. Alabama Crimson Tide

The Alabama Crimson Tide and the LSU Tigers are nearly identical defensively. Both teams have the depth and talent to compete with any offense under the sun.

So far this season, the Tide are giving up eight points per game. If that continues, this team doesn't stand a chance of losing a game.

Led by Dont'a Hightower and Courtney Upshaw at linebacker, the Tide have playmakers all over the field. Hightower is a clone of former Tide 'backer Rolando McClain. He is cerebral, but is also a devastating tackler. Upshaw is an explosive presence off the edge.

Up front, Josh Chapman plugs the middle, and Damion Square provides a push on the outside. However, with the talent behind the line they just need to eat up space and blocks.

The secondary is also loaded with talent. Mark Barron and Robert Lester are a dangerous safety tandem. Lester was the SEC leader in interceptions last season, and Barron is essentially another linebacker playing in the box.

At corner, Dre Kirkpatrick still has unfulfilled potential. DeQuan Menzie and DeMarcus Milliner join Kirkpatrick to give the Tide three very talented cover guys.

At the end of the day, Nick Saban knows how to coach—especially defense. This year is no different.