They spoke for several minutes behind a closed door.
Vaughn played his final three seasons for Popovich and spent the last two seasons as an assistant under Popovich.
"You can look at players on any team and sort of get a feel for who has an intuitive sense of what's going on on the court, and Jacque had that," Popovich told reporters before tipoff.
"I'm a big believer in throwing guys into the mix pretty quickly, and I think you find out about them and save lot of time, whether somebody can handle it or not," Popovich added. "From Day One, I had him present reports to the team and do a lot of things in practice. So from Day One, he had the respect of the players. He was great for us."
Popovich joked that he would begin Sunday's exhibition by sitting on Orlando's bench just to throw Vaughn off.
"He probably will," Vaughn said when told of Popovich's quip. "But I'm trying to imagine what he's going to do. He'll probably put five guards out there just to see the expression on my face."
Vaughn marvels at Popovich's longevity and sustained success. Popovich has compiled a .680 winning percentage over 16 seasons, all with the Spurs.
"He does it year-in and year-out," Vaughn said. "I think that's the most impressive thing. When training camp comes around, he's motivated. He's competitive. He is able to do it year after year. That's a tough task when you have new guys part of the system. He incorporates them and he embraces them.
"I learned a tremendous amount, basketball and otherwise, from him."