INDIANAPOLIS (Reuters) - One of the most unpredictable and compelling NCAA collegiate basketball tournaments in years draws to a close with a Final Four this weekend featuring traditional powers and smaller upstart teams.

South Region top seed Duke faces West Virginia in one semi-final on Saturday at sold-out Lucas Oil Stadium while giant-killing Butler takes on Michigan State in the other.

Duke coach Mike Krzyzewski, whose Atlantic Coast Conference champion Blue Devils are the only number one seeds to make it to the Final Four in Indianapolis, said he was not surprised the 64-team tournament had been full of spectacular upsets.

"There just isn't the difference that there was a decade ago from the top, historic programs and the emerging programs. There are just a lot of good basketball teams right now."

Duke (33-5) will have its hands full with Big East champion West Virginia, a defensive-minded team on a 10-game winning streak and making their first Final Four appearance since 1959.

"My grandfather never missed a game on the radio. There are certainly thousands of other people who grew up the same way," said Huggins who played for the Mountaineers in the 1970s.

"It's hard to get a grasp on how much it means to the state."

The Michigan State-Butler game features a traditional power facing a smaller upstart team whose campus is just six miles from the site of the Final Four.

Lovers of the underdog will be rooting for Horizon League champion Butler (32-4), which eliminated the top two seeds in the tournament's West Region, to topple the 2009 NCAA runner-up Spartans (28-8) who have reached the Final Four in six of the last dozen years.

"It's refreshing that you're looking at four teams that 'team' is maybe the most important thing," said Michigan State coach Tom Izzo.

"It's going to make for a good Final Four in a different way."

(Writing by Steve Ginsburg in Washington, editing by Frank Pingue)