NCAA Tournament 2015: Top Challengers for Prohibitive Favorite Kentucky

The top-ranked Kentucky Wildcats appear to be unstoppable after capping off a 31-0 regular season, and they will enter the NCAA tournament as the clear-cut favorite to win the national title.

It's going to take an off game from Kentucky for a team to even dream of upsetting them amid March Madness. A number of lackluster performances throughout the 2014-15 campaign still haven't been enough to cause the Wildcats to lose.

No one boasts the depth Kentucky does, but several squads have the star power to rise to the occasion and can present certain matchup problems to give the Wildcats fits. The question is whether that will be enough to topple coach John Calipari's juggernaut from Lexington in the end.

Read on for a closer look at the teams best suited to make Kentucky fall in the Big Dance.

Wisconsin Badgers

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Frank Kaminsky is the headliner—the big man who creates nightmares for opposing defenses with his shooting range, ball-handling skills and versatile offensive arsenal.

Even the twin hyphenated bigs Kentucky sports in Karl-Anthony Towns and Willie Cauley-Stein would have a difficult time dealing with "Frank the Tank." And that's not even mentioning Sam Dekker and the emergence of Nigel Hayes.

Big Ten Network highlights just how much of an impact Kaminsky has had en route to earning conference player of the year honors:

Such numbers also show that the uniquely skilled big man has managed to avert foul trouble often and has built on a strong prior season, when he sparked Wisconsin to the Final Four.

Hayes could be the X-factor in pushing the Badgers from national semifinalist contender to a true player for the national title. Senior guard Josh Gasser said as much, per the Milwaukee Journal Sentinel's Jeff Potrykus:

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I tell [Hayes] before every game to be aggressive...Because I truly think he is the guy that can make us from a good team to a great team. We've seen it. When Nigel plays well we tend to play well. That's not to put pressure on him. That's just the type of player he is. He is one of the most versatile players not only in the league but in the country.

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With Kaminsky, Dekker and Hayes starring on Wisconsin's front line, coach Bo Ryan has some unique personnel to work with, as Hayes' athleticism is an added ingredient Ryan hasn't been accustomed to possessing.

The spacing the Badgers can create thanks to the three-point range Kaminsky, Dekker and Hayes all have leads to clean looks at the basket. Against such an athletic Kentucky defense, Wisconsin will need to be firing on all cylinders and have Kaminsky play his best when it matters most.

At least the Badgers have the offbeat rotation and the perfect catalyst in Kaminsky to throw the Wildcats looks they aren't accustomed to seeing.

Duke Blue Devils

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Guard play tends to be a vital part of the March Madness equation. It's hard to find a better backcourt in the country than the one Duke trots out with senior leader Quinn Cook and freshman phenom Tyus Jones.

Kentucky's Harrison twins, Aaron and Andrew, tend to be inefficient as scorers, both shooting well below 40 percent from the field. This is where the Blue Devils can seize a big advantage.

Although Jones and Cook will have to contend with the experience the Harrisons accrued in last year's run to the national final, they were up to the task on a big stage in a recent win at North Carolina, per Duke Basketball:

What this year's Duke squad has that it hasn't in years past is a truly dynamic swingman in Justise Winslow and, more importantly, a legitimate, dominant center in Jahlil Okafor.

Don Shulman of ESPN notes how Winslow is coming into his own at the perfect time:

ESPN's Andy Katz believes Okafor rivals Kentucky's Towns as the potential No. 1 pick in the upcoming NBA draft:

The standout Blue Devils foursome is plenty good enough to win a championship, and junior forward Amile Jefferson gives enough size off the bench to allow Duke to crash the boards well enough to hang with the nation's best.

Duke was the only team to defeat Virginia this season, thanks to a late-game hot streak from the perimeter. It's that type of explosiveness that could give the Wildcats most trouble, especially with the massive edge the Blue Devils figure to have on the perimeter.

Arizona Wildcats

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Virginia is a dubious contender due to the injury to Justin Anderson and how it impacts the Cavaliers' ability to score enough. An absence of true quality wins makes Villanova a less certain commodity.

This leaves Arizona to be the best possible challenger to Kentucky of the remaining lot after Wisconsin and Duke. Coach Sean Miller's squad swept Utah in the Pac-12 slate and defeated Gonzaga earlier in the year to bolster its tournament resume.

As Arizona Basketball points out, almost all of the Wildcats' starting five was distinguished with all-conference honors:

Most of the nation's top talent goes to Kentucky, but first-year forward Stanley Johnson leads Arizona in scoring and presents so many problems with his thick frame and ability to score from anywhere on the floor.

Only Kentucky and Virginia rank above Arizona in KenPom.com's defensive efficiency ratings. This is thanks largely to the presence of Rondae Hollis-Jefferson and savvy senior guard T.J. McConnell.

Zack Rosenblatt of the Arizona Daily Star highlights how much of a one-man wrecking ball Hollis-Jefferson has been with the task of marking the opposition's top scoring threat:

This Arizona team is even better than the one that made the Elite Eight in the 2014 NCAA tournament. Junior Brandon Ashley is now healthy and ready to contribute this time around, and the addition of Johnson has injected the squad with more offensive firepower.

There is a strong blend of experience and rising young stars on this Arizona team to give anyone a real run. Those returning from last year's close call will be eager to get to the next level, which should help players like Hollis-Jefferson and Johnson shine and beat anyone in their path—including, perhaps, Kentucky.