Tournament Challenge: Six perfect brackets left after Middle Tennessee upset

Only six perfect brackets remain out of the approximately 13 million following 15-seed Middle Tennessee's enormous upset over 2-seed Michigan State. Prior to Middle Tennessee's upset, 1,766 perfect brackets remained through the first 20 games of the 2016 NCAA tournament.

The Spartans were picked to advance to the round of 32 in 97.8 percent of brackets (12.7-plus million, the second most); to the Sweet 16 in 91.1 percent of brackets (second most); to the Elite Eight in 80.9 percent of brackets (the most); to the Final Four in 66.9 percent of brackets (second most); to the championship game in 38.6 percent of brackets (second most); and to win the title in 22.3 percent of brackets (second most).

Just 2.2 percent of entries (second fewest) picked Middle Tennessee to advance to the round of 32. Only 1.1 percent of brackets have Middle Tennessee going to the Sweet 16; .8 percent have it going to the Elite Eight; .2 percent have it making the Final Four; and .1 percent have it advancing to the championship game. Fewer than 7,000 brackets (.05 percent) have the Blue Raiders winning the title.

From a historical perspective, the last time a 15-seed won was in 2013 when Florida Gulf Coast beat Georgetown. Since 1985, No. 2 seeds are now 118-8 all-time against No. 15 seeds.

Per ESPN Chalk, Middle Tennessee's victory over Michigan State was the fourth-biggest upset of the past 20 years, according to the point spread. Michigan State closed as a 16.5-point favorite at the Westgate Las Vegas SuperBook.

Michigan State last lost in the first round in 2011.