His backup isn't as shy.
"Cullen is doing an unbelievable job. There's not much more Cullen can do," said Willy Korn, the Tigers' highly touted freshman who got some of the loudest cheers at Death Valley when he threw his first touchdown pass in mop-up duty in the fourth quarter.
He might not get the noisiest ovations, but in just his third start for Clemson (3-0), Harper continues his mastery of the offense. He has 10 touchdowns, no interceptions and has completed 72.5 percent of his passes.
"You just go out there and take what they give you," Harper said.
Harper's ability to take what the offense has been given has been the difference so far for the Tigers. Clemson rushed for just 60 yards, as Furman (1-2) crowded the line of scrimmage and dared the Tigers to throw.
Rising to the challenge, Harper set a school record with a pass efficiency rating of 253.
"He's answered every test so far," Tigers coach Tommy Bowden said.
Even with the easy win, there were still some things to worry Clemson fans. C.J. Spiller, the lightning in Clemson's "Thunder and Lightning" backfield, struggled with nine carries for minus-1 yard. James Davis, the thunder, had 58 yards on nine carries.
Bowden isn't worried as long as defenses crowd the line and Harper can throw it down the field.
"At some point, they are going to loosen up a bit and we'll run better," Bowden said.
The Tigers were outgunned 384-377, allowed five sacks and lost two onside kicks, one to open the second half and one midway through the fourth quarter after Furman's touchdown.
"We won. That's not something Lloyd Carr can say," said Bowden, referring to the coach of Michigan, whose team lost earlier this year to Football Championship Subdivision member Appalachian State, which plays in the Southern Conference in what was formerly known as Division I-AA with Furman.
Clemson has given up an average of more than 401 yards in its past two games. Safety Michael Hamlin blames a lack of focus.
"I know I can play better and the team can play better," said Hamlin, who had an interception and a fumble recovery. "We have our first road test at N.C. State next week and we'll have to be ready to play."
The Tigers have never lost in 20 games against Football Championship Subdivision teams since the group was split off in 1978.
Furman coach Bobby Lamb said his team had to be almost perfect to win, and they weren't. The Paladins threw three interceptions and lost two fumbles. They left at least 14 points on the field because of mistakes and bad breaks.
Jerome Felton's 46-yard run to the end zone on fourth-and-1 in the first quarter was nullified when the Paladins called a time-out seconds before the snap. Mike Brown's 97-yard kickoff return for a touchdown in the second quarter got called back on a block in the back penalty.
"You can't come in here and turn the ball over five times," Lamb said. "We can't fault the play of our kids. They played hard."
Felton gained 74 yards on 20 carries. Starting quarterback Renaldo Gray was 10-for-15 for 70 yards, while backup Justin Sorrells went 18-for-28 for 172 yards.
Clemson has now won 29 in a row over Furman. The Paladins last win came in November 1936, 12-0 in the only home game the Tigers have ever played in the snow.
Furman has lost 15 of its past 16 games against Football Bowl Subdivision teams.
The lone win was 28-3 over North Carolina in 1999.
Furman 0 3 0 7 - 10
Clemson 10 7 7 14 - 38
Clem-Davis 2 run (Buchholz kick), 9:54.
Clem-FG Buchholz 22, 2:09.
Clem-Grisham 49 pass from Harper (Buchholz kick), 9:49.
Fur-FG Beckler 38, :37.
Clem-Ford 33 pass from Harper (Buchholz kick), 8:19.
Clem-Kelly 23 pass from Harper (Buchholz kick), 13:40.
Clem-Harris 42 pass from Korn (Buchholz kick), 10:49.
Fur-Kendall 26 run (Beckler kick), 6:08.
First downs 21 19
Rushes-yards 36-142 33-60
Passing 242 317
Comp-Att-Int 28-43-3 18-22-0
Return Yards (-4) 20
Punts-Avg. 4-21.3 3-49.0
Fumbles-Lost 4-2 2-2
Penalties-Yards 5-30 4-50
Time of Possession 36:33 23:27
RUSHING-Furman, Felton 20-74, Kendall 4-41, Gipson 8-19, LaFrance 3-8, Gray 1-0. Clemson, Davis 9-58, Chambers 4-16, Ford 2-13, Korn 2-8, Faerber 1-6, Spiller 9-(minus 1), Harper 6-(minus 40).
PASSING-Furman, Sorrells 18-28-2-172, Gray 10-15-1-70. Clemson, Harper 16-19-0-266, Korn 2-3-0-51.
RECEIVING-Furman, Sprague 5-56, Truss 5-44, Hedden 4-45, Webb 4-21, McKie 3-21, Mims 3-18, Watson 2-13, K.Williams 1-19, Felton 1-5. Clemson, Kelly 6-79, Grisham 3-74, Ford 2-55, Spiller 2-29, Taylor 2-17, Harris 1-42, Palmer 1-12, Faerber 1-9.