Louisville, Indiana, Miami lead pack

As of 5:30 p.m. Tuesday, there were more than 4 million brackets already entered in Tournament Challenge (last year, there were 6.45 million brackets total).

Not much has changed in terms of the most popular teams to win it all. It's still Louisville, Indiana and Miami as the only teams over 10 percent.

Most popular teams to win the title:

Louisville: 21.5 percent

Indiana: 17.0 percent

Miami: 11.2 percent

Kansas: 8.5 percent

Duke: 8.2 percent

Ohio State: 6.1 percent

Gonzaga: 5.6 percent

Georgetown: 3.6 percent

The least popular team to win it all is still New Mexico State, followed by the Middle Tennessee/St. Mary's winner, then Northwestern State.

The most popular national title game matchups:

Louisville-Indiana: 13.5 percent

Louisville-Miami: 10.6 percent

Duke-Indiana: 6.1 percent

Louisville-Kansas: 5.4 percent

Ohio State-Indiana: 3.8 percent

Duke-Miami: 3.5 percent

  • While 2-seed Ohio State is the most popular pick out of the West (43.2 percent versus 26.9 percent for 1-seed Gonzaga), only 4.2 percent of brackets have the Final Four combination of Louisville, Indiana, Kansas and Ohio State (the favorites to reach the Final Four from each region). On the other hand, 3.9 percent of brackets picked all four No. 1 seeds to reach the Final Four.

  • There's still just one seed upset predicted by users: 9-seed Missouri over 8-seed Colorado State (65.4 percent for the Tigers). The closest matchup according to our users is 6-seed UCLA over 11-seed Minnesota (52.2 percent for the Bruins).

  • And worth watching tonight, the winner of the First Four game between Middle Tennessee and St. Mary's is picked to win in the Round of 64 by 12.6 percent of brackets. It will be interesting to see how much change there will be after the game.