The Tigers (5-2) had lost the past two in the series and had squandered a 12-point lead to trail 31-28 early in the second half. That's when McDaniels and Devin Booker got going for Clemson.
McDaniels had four foul shots and a three-point play while Booker added eight points in the game-breaking run. When Booker hit a pair of free throws with 9:08 to play, Clemson was on top 49-37.
Booker ended with 13 points and eight rebounds. McDaniels had seven boards and five of Clemson's eight blocked shots.
Brenton Williams led South Carolina with 16 points, three days after taking a scary fall in a loss at St. John's. Williams was taken from the court on a stretcher. However, he showed no ill effects from the fall, playing a team high 33 minutes.
These schools have a rivalry in just about everything from athletics to blood drives and grade-point averages. Nothing, though, is bigger than football. Just a week ago, the Gamecocks won their fourth straight over Clemson in the series, 27-17, at Death Valley -- something that only happened once before in a series that began in 1896.
And football was front and center in this one, too. Point guard Ellington, who had two touchdown catches in the Clemson win, returned to the basketball team for his first home game. Ellington's football teammates and coach Steve Spurrier came out at halftime to the cheers of the crowd at Colonial Life Arena.
Spurrier couldn't resist tweaking his latest state rival, saying how the Gamecocks had a big win over a team from the Upstate in South Carolina. "We beat Wofford, 24-7," he said with a smile.
He then acknowledged the Gamecocks' win over Clemson, which made Spurrier the school's all-time victories leader with 65.
Clemson looked like it came out ready for a bit of revenge for the football loss, opening up a 23-11 lead as South Carolina shot just 4 of 14 from the field.
But the Gamecocks closed the half with a 16-5 run as Williams had six points and Mindaugas Kacinas five to cut the margin to 28-27 at the half.
Harrison who started Clemson's decisive run with a jumper before McDaniels hit four straight foul shots. Booker followed with an inside bucket and Jordan Roper had a breakaway jam to put the Tigers up 38-33.
McDaniels had a three-point play, Hall had two of his nine made free throws and Booker scored six straight points to end the run.
Ellington had 12 points and Kacinas 10 for the Gamecocks.
Clemson played for the second straight game without senior forward Milton Jennings, suspended earlier this week after his arrest for drug possession. Jennings has practiced with the Tigers but did not travel to South Carolina.