The third-seeded Blue Devils (22-6) now will have the chance to avenge a loss to arch-rival North Carolina in the regular-season finale last Sunday. The seventh-seeded Tar Heels moved into the semifinals with an 84-72 upset of No. 2 seed Maryland, the defending national champion.
Ewing was on fire for the Blue Devils, making six three-pointers. His long-range accuracy helped Duke keep the Cavaliers in range in the first half, and bury them in the second.
His offensive explosion could not have come at a better time for the Blue Devils because their best long-range shooter, Chris Duhon, scored just one point.
Duke has won the last four ACC Tournament titles, and extended its streak to 13 straight wins in league tournament play.
Meanwhile, Virginia lost its ninth straight ACC Tournament game, five of them under Coach Pete Gillen.
Virginia is known for its spotty defense, and was done in by Duke's 9-for-19 three-point shooting. Also, despite their own 56.9 percent shooting overall and 7-for-12 on three-pointers, it did not help that the Cavaliers committed 19 turnovers.
Devin Smith led the Cavaliers with 19 points, and Elton Brown had 15. With the loss, Virginia end the season at 15-15, and now will have to hope they get a call from the National Invitation Tournament Sunday night.
Meanwhile, the Tar Heels (17-14) rebounded from two solid beatings from the Terrapins in the regular season, 81-66 on Jan. 22 and 96-56 on Feb. 22, and overcame an early nine-point deficit.
"I think there's no question that Sunday's win over Duke gave us the confidence we needed," said North Carolina Coach Matt Doherty. "Having lost to (Maryland) by 40 points and to win by 12, I don't know if that is some kind of record in terms of a loss to a win, but it's got to be something. I don't think anybody gave us a chance here."
They trailed, 40-36, at halftime, then outscored the Terps, 48-32, in the final 20 minutes, and thoroughly outplayed Maryland up front, winning the rebound battle, 40-30.
UNC was led by freshman forward Jawad Williams with 25 points, while Raymond Felton scored 20 and Melvin Scott came off the bench to add 19. He hit 5-of-7 three-pointers.
Drew Nicholas had 18 points for the Terps (19-9), but had an off-night shooting. Steve Blake added 12.
"I'm still proud of this team for finishing with the second seed in the ACC," said Maryland Coach Gary Williams. "We won the games when we had to in order to get into the NCAA Tournament.
I'm proud of that after losing four starters from last year."
Top-seeded Wake Forest moved into the semifinals of the ACC Tournament Friday by easing past upset-minded Florida State, 69-61.
The Demon Deacons trailed, 30-29, at halftime, and faced an 11-point deficit in the opening 20 minutes on a strong defensive effort by the Seminoles, who second in total defense in the league during the regular season.
Josh Howard led Wake Forest (24-4) in scoring with 17 points. He, like the team, played through a tough stretch early as FSU jumped out to a 25-14 advantage.
Justin Gray added 15 points and Vytas Danelius 14 for the ninth-ranked Deacons.
"Every time we have played Florida State, they have played us tough," Gray said. "This was a learning experience for me and the whole team."
The Deacons will play the North Carolina State contest in Saturday's semis. The Wolfpack turned back Georgia Tech, 71-65.
Wake needed a 16-6 run in the second half to pull away from the pesky Seminoles and post their seventh straight win.
A dunk by Anthony Richardson gave the Seminoles a 48-45 lead with 10:38 before Wake Forest rallied.
Gray had a layup and Danelius sank a three-pointer with 9:16 left to tie the game at 50-50 before Wake Forest moved ahead for good on a pair of free throws by Levy.
A dunk by Danelius and two baskets by Howard soon followed before Taron Downey capped the spurt with a three-pointer that made it 61-54 with 5:12 left.
Florida State would get no closer than four points the rest of the way.
"I am thrilled," said Wake Forest Coach Skip Prosser. "We got by a good Florida State team. I've been doing this for about 30 years, and I told the kids that as far as tournament play, I believe one day has almost absolutely nothing to do with the next one."
Tim Pickett scored 17 points and Trevor Harvey 15 for the Seminoles, which lost its seventh straight game to Wake Forest and finished the season 14-15.
"We have made a tremendous amount of progress and improved in a lot of areas (this season)," said Florida State Coach Leoanrd Hamilton. "We just showed that we still need a little work in some areas."
When the North Carolina-Duke and North Carolina State-Wake Forest semifinals unfold Saturday, it will have four schools from North Carolina for the first time since 1963.