Wells was 9 of 13 from the field and 10 of 10 from the free-throw line to lead the seventh-seeded Terrapins (22-11), who delivered the first big shocker of the week in Greensboro and will play third-seeded North Carolina on Saturday in their first semifinal appearance since 2009.
"You have to be good and be lucky to beat a great team. We're a little bit of both," Maryland coach Mark Turgeon said. "Watching them play tonight, I think they fully expected to win that game and that's a good feeling when you have such a young basketball team to play on such a big stage in such a big game and to play with the poise that they played tonight."
They never trailed, held the league's best team from 3-point range to 4-of-25 shooting from beyond the arc, and bolstered their NCAA Tournament credentials by beating Duke for the second straight time.
"One of the things during this time of the year ... is that if you lose, it's final," coach Mike Krzyzewski said. "Our team did not feel that. And now we have to understand that that's the way it is. I mean, if you don't do it, it's done. I don't care what your record was, or whatever. It's over. It's one and done."
Mason Plumlee had 19 points to lead the second-seeded Blue Devils (27-5), whose quest for a No. 1 seed in the field of 68 took a jolt.
North Carolina 83, Florida State 62 • In Greensboro, N.C., P.J. Hairston scored 21 points to help North Carolina beat Florida State in the Atlantic Coast Conference Tournament quarterfinals. Hairston hit five 3-pointers before leaving late in the game with a cut on his left hand, while Reggie Bullock added 17 points for the third-seeded Tar Heels (23-9).
No. 19 Syracuse 58, No. 5 Georgetown 55, OT • In New York, Brandon Triche scored the go-ahead basket early in overtime and Syracuse advanced to the Big East championship game with a victory over Georgetown in the final conference clash of their storied heavyweight rivalry.
The fifth-seeded Orange (26-8) will make their 15th appearance in the tournament title game and go for their sixth crown Saturday night at Madison Square Garden against fourth-ranked Louisville.
No. 4 Louisville 69, Notre Dame 57 • In New York, Russ Smith scored 20 points and Peyton Siva added 12 to lead Louisville to a victory over Notre Dame, the third straight year the Cardinals beat the Fighting Irish in the semifinals of the Big East Tournament.
NCAA Tournament automatic qualifiers
Belmont • Ohio Valley Conference
Bucknell • Patriot League
Creighton • Missouri Valley Conference
Davidson • Southern Conference
Florida Gulf Coast • Atlantic Sun Conference
Gonzaga • West Coast Conference
Harvard • Ivy League
Iona • Metro Atlantic Athletic Conference
James Madison • Colonial Athletic Association
Liberty • Big South Conference
LIU Brooklyn • Northeast Conference
South Dakota State • Summit League
Valparaiso • Horizon League
Western Kentucky • Sun Belt Conference