Which remaining underdog is biggest threat to make Final Four?

Five teams seeded eighth or higher have advanced to this year's Sweet 16, including three in the Southwest Region. Here's a look at which of the five have the best chance to be the unlikely interloper at next week's Final Four in Houston:

1. Florida State (No. 10 seed, Southwest Region)

Outlook: For Florida State to dismantle second-seeded Notre Dame even though Chris Singleton went scoreless in just 10 minutes off the bench, that's a sign the Seminoles have a high ceiling. Four starters scored in double figures and the Seminoles held Notre Dame to 30.9 percent shooting, particularly impressive considering Singleton is one of the nation's best and most versatile defenders. It's hard to believe that Florida State has the scoring punch needed to win two more games, but it would help if the coaching staff can get Singleton reintegrated in the offense. Either way, the Seminoles' defense is good enough to keep them in any game they play the rest of the tournament.

2. Butler (No. 8 seed, Southeast Region)

Outlook: Sequels are rarely better than the original, but Hoosiers, Part II has lived up to its predecessor so far this March. Butler has followed up last year's historic run to the national title game with dramatic victories over Old Dominion and Pittsburgh, advancing to another Sweet 16 behind the play of stars Matt Howard and Shelvin Mack. While the departure of versatile wings Avery Jukes, Willie Veasley and Gordon Hayward has robbed Butler of some of last year's defensive prowess, guard Ronald Nored is still one of the elite defenders in college basketball. How he fares against Wisconsin point guard Jordan Taylor and whether Howard can stay out of foul trouble should determine whether Butler gets a shot at either Florida or BYU in the regional title game. There's no dominant team in this region, and would you count Butler out after last year's run or Saturday's last-second escape against Pittsburgh? {YSP:MORE}

3. Richmond (No. 12 seed, Southwest Region)

Outlook: In its long history as a giant killer, Richmond has beaten a No. 2 seed (Syracuse), a No. 3 seed (South Carolina), a No. 4 seed (Indiana) and three No. 5 seeds (Auburn, Georgia Tech, Vanderbilt). On Friday, the Spiders will get a chance to add top-ranked Kansas to their list of pelts. The size and strength advantage Kansas has in the paint is a concern for Richmond, but the Jayhawks don't exactly have the best track record as a favorite in the NCAA tournament. Kevin Anderson is a Jameer Nelson-esque point guard who controls tempo and scores in a variety of ways, Justin Harper and Dan Geriot are jump-shooting big men who will pull the Kansas big men away from the rim at the other end and the Spiders play a stingy matchup-zone defense. If Kansas doesn't dominate the glass or the paint and Richmond hits from the perimeter, the Spiders are capable of putting a scare into the Jayhawks.

4. Virginia Commonwealth (No. 11, Southwest Region)

Of the 16 teams still alive this week, none are more unlikely than the Rams. They controversially snuck into the NCAA tournament as one of the final four teams in the field, crushed USC in a First Four game and then waylaid Georgetown and Purdue later in the week to advance to their first Sweet 16. The streaky, breakneck-paced Rams are a potentially scary opponent for Florida State, Richmond or even Kansas because they're capable of beating anyone in the nation when at their best, as they were against Purdue. The Rams shot 56.9 percent against the Boilermakers, 65.5 percent in the second half, and had six players finish in double figures. Their 94 points was seven more than anyone had scored on Purdue all season. We know VCU is capable of some clunkers since it lost five of eight games to close the regular season and finished fourth in the Colonial Athletic Association, yet if the Rams stay on this tear, even Florida State's defense is vulnerable.

5. Marquette (No. 11 seed, East region)

Outlook: If someone said before the NCAA tournament began that only two Big East teams would advance to the Sweet 16, Marquette almost certainly wouldn't have been one of the ones projected to make it. The 11th-seeded Golden Eagles upset Xavier and Big East rival Syracuse, advancing to their first Sweet 16 since the Dwyane Wade-led 2003 team made it all the way to the Final Four. There's no Wade-like star on this year's team, which means Marquette will have to attempt to push its way past second-seeded North Carolina on Friday and potentially the winner of Ohio State-Kentucky on Sunday mostly on hustle and grit alone. Marquette needs to keep the tempo slow against North Carolina, put defensive stopper Jimmy Butler on Harrison Barnes, and hope that the trio of Butler, Darius Johnson Odom and suddenly surging sixth man Jae Crowder can score enough points to keep up with the Heels. A finesse team like North Carolina that struggles from the perimeter could be vulnerable on Thursday if Marquette makes it a grind-it-out halfcourt game, but two upsets in this daunting region seems like too much to ask.

The Rams shot 56.9 percent for the game, 65.5 percent in the second half. Six VCU players finished in double figures. Point guard Joey Rodriguez scored 12 points and added 11 assists. His nickname is "Boo Boo," but you wouldn't have known it Sunday night. He didn't have a single turnover in 34 minutes of play.

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