Duke has won a record 17 straight ACC tournament games, and is seeking to become the first team in the conference to win six straight championships. The Blue Devils haven't dropped a tourney game since an 83-68 loss to North Carolina in the 1998 final.
With the game tied in the second half, Duke earned its seventh straight trip to the championship game by scoring on 20 of 22 possessions to close the game.
The Blue Devils did it in several ways, scoring on drives, passes off penetration and offensive rebounds. They led by as many as 20 points and committed no turnovers after the break.
"I just thought we were stronger with the ball in the second half, especially with our drives, and we found an incredible number of guys open after driving," Duke coach Mike Krzyzewski said.
"It's just really as efficient on the offensive end as we've played all year. To me, it was beautiful basketball."
Last week, Georgia Tech (23-9) used its athleticism and physical defense to beat the Blue Devils 76-68, ending Duke's 41-game home winning streak. The Yellow Jackets blocked 11 shots, forced 20 turnovers and held Duke to 34 percent shooting in that game.
Duke returned the favor Saturday, playing tough defense and taking the ball to the hole during a decisive 17-4 run midway through the second half.
The Blue Devils shot 52 percent and got 46 points in the paint, many coming on layups by Williams and Deng after penetration from Duke's guards. They also had just six turnovers, and hit 25 of 38 free throws.
"We just felt that they out-toughed us in Durham," Duhon said. "They got every loose ball, every rebound. We didn't fight. So today we made it a point to go out and fight those guys. Shelden did a magnificent job and we just fed off him."
Williams, a 6-foot-9 sophomore controlled the inside for the second straight game. He went 6-for-8 from the floor and 8-for-12 from the line. In Friday's quarterfinal win against Virginia, Williams had a career-high 27 points to go with eight rebounds.
"I knew coming in it was going to be a big, physical game," Williams said. "I knew if I put myself in position where I don't pick up any cheap fouls, I can help my team in the long run. That was one of the things I was concentrating on."
B.J. Elder scored 25 points to lead the Yellow Jackets, who were making just their second semifinal appearance since 1996.
He also had three blocks and no fouls in 37 minutes Saturday.
The teams were tied at 46 on Elder's stickback with 14:20 to play, but Daniel Ewing put the Blue Devils ahead to stay with a 3-pointer on the next possession.
The Blue Devils started taking the ball inside from there. Duhon drove past Will Bynum for a layup, then penetrated to find Deng on the baseline for a three-point play for a 54-46 lead. Deng also had a layup off penetration by J.J. Redick.
During the run, Duke got to the line, hitting 6 of 7 free throws, while holding the Yellow Jackets to 1-for-6 shooting. They also got several baskets off offensive rebounds, part of 12 second-chance points after halftime.
Duke outrebounded Georgia Tech 37-31, which Georgia Tech coach Paul Hewitt said was caused by the Yellow Jackets' inability to stop penetration.
"They got too many second shots," Hewitt said. "The reason for that is probably we allowed so many times for them to drive to the middle and we had to start helping that it opened offensive rebounding lanes. They beat us off the dribble too many times during that run, got into the paint and forced us to help."
Duhon's runner made it 63-50 with 9:42 to play, and Georgia Tech got no closer than 10 after that.
"It was typical Duke," said Marvin Lewis, who had just five points. "They denied the passing lanes. And they rebounded and played harder than us."