The two-time defending champions survived a huge scare, Turkey having chances to go three points up with nine seconds remaining in OT, only for Dogus Balbay and Cedi Osman to miss free-throws.
USA head coach Popovich said the encounter showed the defending champions still had plenty of work to do at the tournament in China.
"It was a heck of a game," he said.
"As we all know, it was anybody's game. We will accept the win, but it was anybody's to win.
"The team that we played tonight again showed its experience and the improvement we have to make execution-wise. We're not there yet. We're still trying to get better at that.
"But, playing a fine team like that gives us another good example of how we can be when everybody knows what they're supposed to be doing on the court.
"So, I give them a lot of praise for what I saw."
USA round out their Group E campaign against Japan on Thursday.