Max Schrock's leadoff double to right field in the second forced Johnson to work out of the stretch, which proved troublesome last weekend. The results were worse on Sunday.
The junior lefty was able to force a groundout and fly out before exiting, but not before issuing a pair of walks and giving up three more RBI hits that put UNC in a 5-0 hole.
"It was certainly disappointing," UNC head coach Mike Fox told reporters following UNC's worst loss of the season. "I really thought Hobbs was going to be ready. Again, the key with him is his fastball command. The walk to [Chase] Vergason was the killer there in the second inning. That was the killer, because it opened the door for the next three batters.
"We make a good pitch on Pankake and, to his credit, he fights it off and hits the ball down the line. Then we got two strikes on Dantzler. He throws two really good pitches and then leaves a ball up right where he likes it."
Pankake's double to left field scored two runs, as did Dantzler's single to right field.
"We got a couple of chances early to get a few runs across and we got a couple of key hits," Pankake said.
Tanner English, who opened the scoring on a RBI squeeze bunt for a single, said the Gamecocks' intent was to put pressure on Johnson early to force him to make pitches.
"It was just terrible," Johnson said of his performance. "I was not locating, balls up in the zone, and against a good hitting team, that's what's going to happen."
Last Sunday, Florida Atlantic managed to attack Johnson by making him work out of the stretch in the sixth and seventh innings, drawing three walks over his final five batters.
"My release point is going to be different out of the windup than it is in the stretch," Johnson said on Thursday. "It was just harder for me to find it out of the stretch for that inning."
Pitchers traditionally shift from the windup to the stretch with a runner on base to better counter steal attempts. The stretch is a simpler throwing motion that requires less footwork as the plant foot is already positioned parallel to the rubber.
Working out of the stretch wasn't the prime culprit in Johnson's struggles on Sunday, although it was a factor.
"Today it wasn't as bad," Johnson said. "I just didn't make the pitches I needed to and I didn't locate in and out the way I needed to."
The Rocky Mount, N.C. native's final line consisted of five earned runs, five hits, three walks and a strikeout in 1.2 innings. Sunday marked his shortest career outing in a start. The five earned runs are also a career high.
That's surprising considering a late-season hot streak – six earned runs allowed in his previous eight starts – that led to Fox and pitching coach Scott Forbes moving Johnson into the No. 2 starter's spot for NCAA Tournament play.
Johnson's early exit mirrored Saturday's outing by Kent Emanuel, who allowed four earned runs on seven hits in 2.1 innings.
UNC's starting weekend rotation - Emanuel, Johnson & Benton Moss - have combined to give up 24 earned runs and 31 hits in 24.0 IP in NCAAT play, good for a 9.00 ERA.
Moss (8-1, 3.78 ERA) will start Monday's deciding third game for UNC. South Carolina will counter with rookie southpaw Jack Wynkoop (7-3, 2.92 ERA).