ATLANTA (AP) -- Mike Krzyzewski says junior Lee Melchionni struggles with his confidence at times.
"He's still trying to figure out is he a good player or not," the Duke coach said.
When Melchionni launched a couple airballs Wednesday night against Georgia Tech, he might have had more reason for self-doubts, but he kept shooting and his two late 3-pointers lifted the Blue Devils (No. 10 ESPN/USA Today, No. 7 AP) to a 60-56 victory.
"He is a good player," Krzyzewski said. "That's a huge step for Lee."
With Tech focusing its defense on J.J. Redick, Melchionni snapped a 49-49 tie with a 3-pointer from the corner with 3:15 left. He added another 3 with 1:26 left for a 57-52 lead.
"I couldn't be happier," said Melchionni, who finished with nine points. "I just let them go. They felt good. I'd had two airballs, so the next two just had to go in."
Krzyzewski was even happy with a late miss from Melchionni.
With Duke leading 57-54, Melchionni missed a shot from the top of the circle as the shot clock expired, but Daniel Ewing grabbed the rebound for the Blue Devils and was fouled with 31 seconds left.
"That was probably as important a play as there was in the basketball game," Krzyzewski said.
Ewing missed two free-throw attempts, but the second miss was rebounded
by Duke's Shelden Williams, again preventing Tech from taking possession.
Mario West was called for a foul on the inbounds play, and Redick, who led Duke with 21 points, made two free throws to push the lead back to four.
With the win, Duke continued its dominance of its series with Georgia Tech.
The Blue Devils (20-4, 10-4 Atlantic Coast Conference) have won 18 of the last 19 games in the series, including nine straight at Alexander Memorial Coliseum. They reached the 20-win mark for the 21st time under Krzyzewski.
Jarrett Jack led Tech (15-9, 6-7) with 20 points and Schenscher added 16.
The Yellow Jackets, who have not won consecutive games since early January, lost despite holding Duke to 33.9 percent shooting.
"It was a very, very difficult game for us," Tech coach Paul Hewitt said. "At home if you hold somebody to 34 percent you have to be able to win those types of ballgames."
Hewitt said the Yellow Jackets' defense has not faltered but the offense continues to struggle. B.J. Elder, limited to four minutes in the first half after picking up two fouls, was held to two points.
The loss leaves Tech still unsure about its NCAA Tournament hopes.
"We're not really in a panic mode, we just know this game Saturday at Miami is going to be a big one for us," Elder said.
Jack, who became accustomed to taking the lead role for Tech when Elder missed nine games and most of another with a strained left hamstring early in the ACC schedule, had 14 first-half points.
Duke countered with the outside shooting of Redick and Ewing, who combined for 27 points in the first half that ended in a 33-33 tie.
Tech missed its first 11 shots from the field in the second half until Elder finally broke the drought with his first basket of the game at the 13:52 mark. But Duke also struggled early in the half as its foul troubles worsened.
Ewing was called for his fourth foul less than five minutes into the half, and Nelson picked up his fourth at the 12:05 mark. Krzyzewski turned to sophomore Patrick Davidson, who had logged only 12 minutes in conference games.
Redick scored Duke's first points of the second half on a 3-pointer but he didn't score again until the free throws in the final seconds.
Ewing had 14 points for Duke, while Williams added 12, 10 in the second half.
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Maryland point guard Melo Trimble, considered a lock to leave the program before struggling in the second half last season, has withdrawn from the NBA draft and will return for his junior season.
Louisville's Chinanu Onuaku, who recently underwent a medical procedure to correct a heart rhythm issue detected during the combine, will keep his name in the NBA draft pool.
Andrew White III will return to the Nebraska men's basketball team next season after removing his name from the NBA draft.