GREENSBORO, N.C. -- Maryland Dez Wells scored 30 points while second-ranked Duke suffered through a miserable shooting performance from the perimeter, allowing the Terrapins to pull off an 83-74 stunner in the Atlantic Coast Conference tournament Friday night at the Greensboro Coliseum.
Maryland (21-11) will play in Saturday afternoon's second semifinal against the winner of Friday's Florida State-North Carolina game.
Seventh-seeded Maryland, which probably has to win the ACC tournament to land a spot in the NCAA tournament, never trailed against Duke (27-5).
Four other Maryland players -- Nick Faust, Alex Lin, Jake Layman and Seth Allen -- scored 10 points each.
Mason Plumlee scored 19 points to place Duke, which shot 4 for 25 on 3-point attempts. Rasheed Sulaimon added 16 and Seth Curry had 15.
Duke's quest to land a No. 1 regional seed for the NCAA Tournament could be damaged even though it won five of its last six regular-season games since losing Feb. 16 at Maryland. Four of those victories were by double-digit margins and the other came against regular-season champion Miami.
Maryland scored five of the first seven points in the second half to lead 39-28. A four-point play by Duke's Seth Curry ignited an 8-2 run, causing Maryland to call timeout.
Duke was within 45-44 on Ryan Kelly's three-point play before the Terrapins took off again, cranking their lead to 65-52 with less than six minutes to play.
The Blue Devils were within 67-60 with four minutes to play.
Duke fell to 17-1 all-time against the tournament's No. 7 seed.
Maryland held a 12-point lead before settling for a 34-26 halftime advantage. The lead was built mostly on the strength of six 3-point connections.
Maryland bolted to a 12-2 edge and that set the tone for the opening half. The Terrapins drained four 3-point shots in slightly more than 10 minutes, giving them a 22-14 lead.
At that point, Wells had 14 points, matching Duke's team total. Sulaimon came off the bench to scored 10 of his team's first 14 points.
Duke made only 1 of 10 attempts from 3-point range in the first half, a startling development for a team that entered the game with an ACC-leading 41.6-percent shooting clip on 3-pointers.
NOTES: The teams split regular-season games, with Duke winning 84-64 on Jan. 24 at home before losing 83-81 on Feb. 23 at Maryland. ...Duke was the No. 2 seed in the tournament for the third year in a row. ... Duke's most recent game in the Greensboro Coliseum was its stunning loss to Lehigh in its NCAA tournament opener last March. ... Duke entered the tournament having won 11 consecutive ACC quarterfinal games when receiving a first-round bye. ... Maryland's defense ranked first in the ACC in field-goal percentage defense, holding opponents to 37.9 percent shooting from the field in the regular season. ... Duke's Ryan Kelly, who returned for the final three games of the regular season after sitting out with a foot injury, didn't play in either previous game against Maryland this season.