The Huskies, the last team to defeat Florida's Gators, will play equally surprising Kentucky for the NCAA championship on Monday in the Dallas Cowboys' home stadium at Arlington, Texas.
Kentucky's young Wildcats beat Wisconsin 74-73 on Aaron Harrison's clutch three-pointer with less than six seconds to play in the second semi-final as more than 79,000 fans looked on.
"I didn't play that well today but I hit a big shot," said Harrison after his third consecutive game-winning three-pointer.
The Wildcats, who start five freshmen, will be aiming for their second national title in three seasons and ninth overall.
Connecticut has won three previous championships, the last in 2011.
Forward DeAndre Daniels sparked Connecticut in its shock win over Florida, contributing 20 points and 10 rebounds as the Huskies took control after trailing by 12 points early in the contest.
"We feel like we have been doubted the whole season," Daniels told reporters after the big win. "But that's what drives us ... We like to go out and try to prove people wrong."
Guard Shabazz Napier, key to Connecticut's 65-64 victory over Florida on Dec. 2, added 12 points and six assists and stole the ball four times from the Gators, who were the top seed in tournament.
Florida had not lost since the December encounter with Connecticut but could not handle the Huskies' sharper shooting and better defense.
Center Patric Young led Florida with 19 points and forward Casey Prather added 15. But top guard Scottie Wilbekin had only four points and Frenchman Will Yeguete just two.
In a game of streaks, Kentucky used its size and inside play to take down Wisconsin.
Guard James Young scored 17 points and forward Julius Randle added 16 before Harrison hit his only three-pointer of the game to wrap up the win.
Ben Brust and Sam Dekker each had 15 points for Wisconsin, which hit eight three-pointers.
But the one the Badgers needed most, Traevon Jackson's last second shot, rolled off the rim, ending the game.