CHAPEL HILL, N.C. — The losses are adding up for North Carolina, along with the sleepless nights for Hall of Fame coach Roy Williams.

The Tar Heels have their worst record through 15 games in 17 seasons under Williams. They’ve struggled to replace veteran and NBA talent from a team that earned a No. 1 seed in last year’s NCAA Tournament. And the roster left behind has been hit hard by injuries, notably with potential one-and-done prospect Cole Anthony roughly midway through a multi-week timeline to return from knee surgery.

It has already left the Tar Heels with a major climb ahead to earn a bid to the NCAA Tournament, not to mention the fact they look as vulnerable as they ever have for Clemson to end its 0-for-forever streak in Chapel Hill on Saturday.

It all has Williams - who said on his radio show earlier this week that it is the “least gifted” team he’s had since taking over at UNC - staying up late looking at statsheets, planning practices or reviewing scouting reports searching for a way to stop UNC’s struggles.

“I’ve never been one to sleep. I’m not sleeping at all now,” Williams said Friday. “That’s the only difference.

“The only thing is when you’re winning it’s easier to finally go to sleep. A normal night for me is 4½ to five hours. Now it’s nowhere close to that.”

The Tar Heels (8-7, 1-3 Atlantic Coast Conference) peaked at No. 5 in the Top 25 in November, but they’re No. 108 in the NCAA’s NET rankings. They haven’t been effective at either end of the floor, ranking 83rd in KenPom’s adjusted offensive efficiency (105 points per 100 possession) and 72nd on defense (94.3).

They’re coming off home losses to Georgia Tech and Pittsburgh, both picked to finish in the bottom third of the ACC. Now they’re hosting the Tigers (7-7, 1-3), who are 0-59 in Chapel Hill to give UNC the longest home winning streak against a single opponent in NCAA history.

Even the 2002 team that went 8-20 under Matt Doherty kept that streak alive, and by a double-figure margin, too.