Former President Barack Obama attends Duke-North Carolina, wishes Zion Williamson well

Former President Barack Obama was in attendance for Wednesday night's upset by the No. 9 North Carolina Tar Heels of the No. 1 Duke Blue Devils at Cameron Indoor Stadium. 

Duke University officials had increased security with the likelihood that Obama would be in attendance, a person with knowledge of the situation told USA TODAY Sports earlier Wednesday. 

The person requested anonymity because they were not authorized to speak on the matter. 

Obama was video-taped pregame by ABC11's Mark Armstrong high-fiving fans and later was captured by ESPN cameras. 

The former president even had a front-row view at Zion Williamson's bizarre knee injury, which was the result of the Duke star freshman's shoe blowing apart when he planted. 

After taking in the contest, which resulted in a big UNC win, Obama took to Twitter to wish Williamson well. 

Duke coach Mike Krzyzewski told reporters after the game that Williamson had suffered a "mild knee sprain," but said his star's knee was otherwise "stable."

Obama was the talk of Tuesday's news conference with the teams, with Duke's R.J. Barrett thrilled about the possibility of the former president possibly attending.

"If he comes, I'm going to be very excited," Barrett told reporters. "This is a legendary game. Many people want to watch. It's going to be a great game."

The Tar Heels (20-5, 10-2) are looking to upset the heavily favored Blue Devils (23-2, 11-1) in the first of two clashes in the next three weeks. Behind Barrett and projected No. 1 NBA draft pick Williamson, Duke is currently the top overall No. 1 seed in USA TODAY Sports' latest bracketology. North Carolina is a projected No. 2 seed. 

Obama has close ties to UNC coach Roy Williams and often favored the Tar Heels in his NCAA tournament picks while he was president. 

“I never know who is coming,” Duke coach Mike Krzyzewski told reporters Tuesday. “I try not to let that be what I’m thinking of. Look, anybody can show up here because it is a bucket-list thing. It’s a bucket-list just to come to a game in Cameron. But Duke and Carolina at Cameron is one of those great sporting events. So we can expect anything here."

Tipoff for the game is 9 p.m. ET on ESPN, and tickets were nearing the price of Super Bowl tickets.