Irmo star Mustafa Greene returned to action Friday at W.C. Hawkins Stadium, but Dorman sophomore running back Raymond Smith stole the show.
Smith ran for a career-high 167 yards and a touchdown as the Cavaliers ended the Yellow Jackets' season with a 14-0 victory.
Dorman (12-1) moves on to the Class 4A Division I semifinals next week against Region 2-4A rival Gaffney.
Irmo ends the season at 11-2.
"The offensive line made the holes, and I just ran my hardest," said Smith, whose previous high was 95 yards against Spartanburg in the regular-season finale.
"The plan tonight was to be balanced, but once we saw we could run the ball, we just kept pounding it."
In the end, Dorman rolled up 247 rushing yards, 324 total, on the Yellow Jackets' defense.
One reason the Cavaliers were so focused on the running game was an injury to big-play receiver Charone Peake.
"With Charone at maybe 50-60 percent, that made us do things a little differently than we have been," Dorman coach Dave Gutshall said.
"We needed a running back to come up big, and Raymond Smith did."
Meanwhile, the Dorman defense limited Irmo to 163 yards. Even with senior star Mustafa Greene back in the lineup, the Yellow Jackets' bread-and-butter running game produced 74 net yards. Greene, still hobbled by a high ankle sprain, closed his career with 82 yards on 19 carries.
"We came up short on two fourth-down plays in the first half, and maybe things might have gone a little differently had we made them. But the bottom line was Dorman had a good defense," Irmo coach Bob Hanna said.
"Obviously, they created a lot of problems for us offensively. The kids played hard and never quit. I think we just ran into a team that was a little bit better than us."
Irmo's best scoring chance came on its first possession of the second half. The Yellow Jackets marched from their own 36 for the Dorman 21, but the drive ended when Adam Humphries batted down a fourth-down pass intended for Mitwain Brown in the end zone.
Dorman took over and put together two consecutive scoring drives to break the scoreless duel.
Smith's 27-yard scoring run capped an eight-play, 74-yard march. Next, Johnny Foster hit Ron Greene with a 27-yard touchdown pass with 8:09 to go in the fourth quarter to conclude a nine-play, 67-yard scoring move.
Dorman 0 0 7 7-14
Irmo 0 0 0 0-0
D- Raymond Smith 27 run (Paul Inclan kick), 2:12
D- Rob Greene 27 pass from Johnny Foster (Inclan kick), 8:09
First downs 16 9
Rushing 41-247 28-74
Passing yards 77 89
At-Com-Int 12-8-1 21-9-1
Fumbles-lost 1-1 1-0
Penalties 7-50 9-55
Punts 3-98 4-118
RUSHING- D, Foster 4-16, Smith 18-169, Tucker 8-42, Booker 4-16, R. Greene 2-6, Peake 1-4. I, M. Greene 19-82, Olson 8-(-7).
PASSING- D, Foster 8-12-1-77. I, Olson 9-21-1-89.
RECEIVING- D, Peake 2-0, Bomar 1-12, Humphries 1-11, Cohen 1-6, R. Greene 1-27 Tucker 1-8. I, Richardson 3-25, Scott 1-11, Brown 2-13, Frazier 1-6, M. Greene 1-14, Scott 1-11.