Louisville is the tournament's overall top seed and the nation's new No. 1 team, but if the Cardinals are to emerge out of the Midwest Regional, they'll have to negotiate an imposing bracket that features several potential obstacles.

The Cardinals (28-5) are one of the hottest teams in the nation, entering the tournament with a 10-game winning streak and Big East regular season and tournament championships. They've lost only twice in their last 22 games.

Second-seeded Michigan State won the Big Ten's regular-season title and was in the discussion for a No. 1 NCAA seed until losing to Ohio State in the league tournament. They're joined in the Regional by defending national champion Kansas, which won the Big 12 regular-season crown and Wake Forest, ranked No. 1 in the nation in January.

The Midwest also features an Ohio State team that reached the Big Ten championship game; Boston College, which nearly beat Duke in the Atlantic Coast Conference tournament and Pacific-10 tournament champion Southern California.

Arizona, the 12th seed, is bit of a surprise entry after being viewed as a bubble team entering the day. Louisville opens tournament play Friday in Dayton, Ohio, against the winner of Tuesday's opening-round play-in matchup between Alabama State and Morehead State.

Next up is the winner of the Ohio State-Siena game. The eighth-seeded Buckeyes won five of their last seven (losing twice to Purdue). Siena is the potentially dangerous champion of the Metro Atlantic Athletic Conference. The Saints, who upset Vanderbilt in the first round last year as a No. 13 seed, have won 16 of their last 18 games.

The second-seeded Spartans, who have to be eyeing a shot at the Final Four in Detroit, near their East Lansing home, open Friday in Minneapolis against Robert Morris. A win there will send them into a second-round game against the Boston College-Southern California winner.

Third-seeded Kansas, coming off a stunning Big 12 tournament loss to Baylor, opens defense of its NCAA title Friday in Minneapolis against North Dakota State, which won the Summit League championship and made the NCAAs in its first year of eligibility after a five-year reclassification period from Division II.

A win there will send the Jayhawks into a second-round battle against the victor in the West Virginia-Dayton game. The Mountaineers played well coming down the stretch, upsetting Pittsburgh in the Big East tournament and taking Syracuse to overtime in the semifinals.

The Flyers are an at-large selection from the Atlantic 10, after losing four of their last seven games.

Arizona, which made the field despite dropping five of its last six games, snuck into the tournament for the 25th year in a row. The Wildcats have a first-round matchup against fifth-seeded Utah, which earned the Mountain West tournament title, and has won 12 of its last 14 games.

A young but talented Wake Forest team got the fourth seed. The Demon Deacons feature one of the biggest front lines in the nation, but fell off a bit down the stretch, losing six of their last 14 games after ascending to the No. 1 spot in the rankings.

The Deacons are matched up in the first round with a potentially pesky Cleveland State club, which upset Butler to win the Horizon League championship and also won at Syracuse early in the season.

Louisville boasts a deep, experienced team with Earl Clark, Terrence Williams, Jerry Smith and Edgar Sosa. It nearly made the Final Four a year ago before falling to North Carolina in the regional final, in front of a heavily pro-Tar Heels crowd in Charlotte.

The Cardinals appear to be the most talented club in this bracket and coach Rick Pitino, who took UL to the Final Four in 2005, brings a wealth of postseason experience, but face a far from easy road to Detroit.