The Tar Heels led by three in the final 90 seconds before falling 67-65 to South Carolina on Tiffany Mitchell's driving basket with 4.2 seconds left in Friday night's NCAA Tournament Sweet 16 game. Most notably, there was a hurried missed shot from Latifah Coleman with 1:24 left, a loose offensive rebound on a missed free throw that set up Olivia Gaines' bounce-around-the-rim tying 3-pointer, then a missed contested 3 from Jessica Washington that led to Mavunga fouling out while battling for the rebound underneath. There was also a turnover when Mavunga threw an outlet pass off a rebound to Coleman, only to have her bumped by a defender at the sideline and go out of bounds with 3:17 left. [...] Mitchell answered a tying basket from Jessica Washington in the final minute by driving past Brittany Rountree for what turned out to be the winning score. Fourth-seeded UNC (26-9) had one more chance, but freshman Jamie Cherry's desperation runner hit all backboard as the horn sounded, sending the Gamecocks into an oncourt celebration. [...] Dawn Staley's Gamecocks are back to face the Arizona State-Florida State winner on Sunday to go to the Final Four. Washington's drive to tie it with 27.2 seconds left was UNC's last basket of the season.